Combination of Sequence | B.Stat Objective | TOMATO 79

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Combination of Sequence.

Logic and combination of sequence (B.Stat Objective)


The two sequence of numbers {1,4,16,64,.....} and {3,12,48,192,.....} are mixed as follows {1,3,4,12,16,48,64,192,....}. One of the numbers in the mixed series is 1048576. Then the number immediately preceeding it is

  • 262144
  • 786432
  • 814572
  • 786516

Key Concepts


Logic

Sequence

Integers

Check the Answer


Answer: 786432.

B.Stat Objective Question 79

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


The first series is of form \(4^{r}\) for \(r \geq 0\) \(r \in\) set of natural numbers the second series is of form \(3 \times 4^{r}\) for \(r \geq 0\) \(r \in\) set of natural numbers and the third series is of \(4^{r}\),\(3 \times 4^{r}\) in alternate element form for \(r \geq 0\) \(r \in\) set of natural numbers

given that 1048576=\(4^{r}\)=\(4^{10}\)

then preceeding term \(3 \times 4^{9}\)=(3)(262144)=786432.

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Logic and Group | TOMATO B.Stat Objective Question

Try this problem from I.S.I. B.Stat Entrance Objective Problem based on Logic and Group.

Logic and Group ( B.Stat Objective Question )


Four passengers in a compartment of the Delhi-Howrah Rajdhani Express discover that they form an interesting group. Two are lawyers and two are doctors. Two of them speak Bengali and the other two Hindi and no two of the same profession speak the same language . They also discover that two of them are Christians and two Muslims, no two of the same religion are of the same profession and no two of the same religion speak the same language. The Hindi speaking doctor is a christian.Then which one holds

  • BLM
  • CLB
  • BDC
  • BDH

Key Concepts


number Series

Logic

Integers

Check the Answer


Answer: CLB

B.Stat Objective Problem

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


one doctor HDC then other doctors by given conditions is BDM

then other two LM and LC and for DMB then LM is H that is HLM

Then LC is B that is BLC or CLB.

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Composite number Problem | B.Stat Objective | TOMATO 75

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Sequence and composite number.

Composite number Problem (B.Stat Objective)


Consider the sequence \(a_1\)=101, \(a_2\)=10101,\(a_3\)=1010101 and so on. Then \(a_k\) is a composite number ( that is not a prime number)

  • if and only if \(k \geq 2\) and \(11|(10^{k+1}+1)\)
  • if and only if \(k \geq 2\) and k-2 is divisible by 3
  • if and only if \(k \geq 2\) and \(11|(10^{k+1}-1)\)
  • if and only if \(k \geq 2\)

Key Concepts


Logic

Sequence

Composite number

Check the Answer


Answer: if and only if \(k \geq 2\) and k-2 is divisible by 3

B.Stat Objective Question 75

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


for \(a_k\) \(k \geq 2\) may be prime also then not considering this here

for \(a_{8}\) \(10^{9}-1\) and \(10^{9}+1\) not divisible by 11

8-2 is divisible by 3 and \(a_{8}\) is composite number then \(a_{k}\) is composite if and only if \(k \geq 2\) and k-2 is divisible by 3.

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Logic and Integers | B.Stat Objective | TOMATO 73

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Logic and Integers.

Logic and Integers (B.Stat Objective problems)


Let P denotes the set of all positive integers and \(S={(x,y):x\in P,y \in P} and x^{2}-y^{2}=666\) The number of distinct elements in the set is

  • 1
  • 0
  • 2
  • more than 2

Key Concepts


Logic

Relations

Integers

Check the Answer


Answer: 0

B.Stat Objective Question 73

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


\(x^{2}-y^{2}=666\) for all pairs of factors of 666

1 and 666, 2 and 333, 6 and 111, 9 and 74, 18 and 37 such that given condition holds

x and y are non integers then number of distinct elements in the set in the set is 0.

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Integer and Divisibility | B.Stat Objective | TOMATO 69

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Integer and Divisibility.

Integer and Divisibility (B.Stat Objective problems)


Every integer of form \((n^{3}-n)(n-2)\) for n=3,4,..... is

  • divisible by 12 but not always divisible by 24
  • divisible by 6 but not always divisible by 12
  • divisible by 24 but not always divisible by 48
  • divisible by 9

Key Concepts


Logic

Integers

Divisibility

Check the Answer


Answer: divisible by 6 but not always divisible by 12

B.Stat Objective Question 69

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


\((n^{3}-n)(n-2)=n(n^{2}-1)(n-2)=(n-1)n(n+1)(n-2)\)

(n-1)n(n+1) is divisible by 3 and any two consecutive integers is divisible by 2 gcd(2,3)=1

then 6|(n-1)n(n+1) and minimum (n-2)=1 for n=3,4,.... then \((n^{3}-n)(n-2)\) divisible by 6 but not always divisible by 12.

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Logic and speed | AIME I, 2008 | Question 3

Try this beautiful problem from the American Invitational Mathematics Examination I, AIME I, 2008 based on Logic and Speed.

Logic and Speed - AIME I, 2008


Ed and Sue bike at equal and constant rates and they swim at equal and constant rates. The same way they jog at equal and constant rates. ed covers 74 kms after biking for 2 hrs, jogging for 3 hrs and swimming for 4 hrs while sue covers 91 kms after jogging for 2 hrs swimming for 3 hrs and biking for 4 hrs. Their biking jogging and swimming rates are whole numbers of km/hr, find the sum of the squares of Ed's biking jogging and swimming rates.

  • is 107
  • is 314
  • is 840
  • cannot be determined from the given information

Key Concepts


Logic

Speed

Integers

Check the Answer


Answer: is 314.

AIME I, 2008, Question 3

Elementary Number Theory by David Burton

Try with Hints


Let a,b, c be biking jogging and swimming rates then 2a+3b+4c=74 first eqn and 4a+2b+3c=91 second eqn subtracting second from first eqn gives 2a-b-c=17 third eqn

third eqn multiplied by 3 + first eqn gives 8a+c=125 gives \(a \leq 15\) third eqn multiplied by 4 +first eqn gives 10a-b=142 gives \(a \gt 14\)

then a=15 and b=8, c=5 and \(a^{2} +b^{2} + c^{2}\)=225+64+25=314.

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Logic True-False Reasoning | B.Stat Objective | TOMATO 67

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Logic True-False Reasoning.

Logic True-False Reasoning (B.Stat Objective problems)


P,Q, R are statements such that if P is true then at least one of the following is correct (i) Q is true (ii) R is not true then

  • if both Q and R are true then P is true
  • if both P and Q are true then R is true
  • if both P and R are true then Q is true
  • none of these

Key Concepts


Logic

Relations

True-False

Check the Answer


Answer: if both P and Q are true then R is true

B.Stat Objective Question 67

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


P true gives (i) holds and (ii) do not hold that is Q true and R true

P true gives (i) do not hold and (ii) holds that is Q non true and R non true

then from given conditions when P true and first condition holds that is Q true then second condition do not hold that is R is true that is if both P and Q are true then R is true.

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Logic and True-False | B.Stat Objective | TOMATO 65

Try this TOMATO problem from I.S.I. B.Stat Entrance Objective Problem based on Logic and True-False.

Logic and True-False (B.Stat Objective problems)


Let P,Q,R,S be four statements such that if P is true then Q is true, if Q is true then R is true and if S is true then at least one of Q and R is false then it follows that

  • if S is false then both Q and R are true
  • if at least one of Q and R is true then S is false
  • if P is true then S is false
  • if Q is true then S is true

Key Concepts


Logic

Relations

True-False

Check the Answer


Answer: if at least one of Q and R is true then S is false

B.Stat Objective Question 65

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


P true implies Q true and Q true imples R true

S true implies Q false with R false

then R true implies Q true implies P true with S false then if at least one of Q and R is true then S is false.

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Relations and Numbers | B.Stat Objective | TOMATO 63

Try this TOMATO problem from I.S.I. B.Stat Objective based on Relations and Numbers.

Relations and Numbers (B.Stat Objective problems)


We consider the relation , "a person x shakes hand with a person y".Obviously if x shakes hand with y, then y shakes hand with x. In a gathering of 99 persons , one of the following statements is always true, considering 0 to be an even number, find which one is it.

  • there is at least one person who shakes hand with an odd number of persons
  • there is at least one person who shakes hand with an even number of persons
  • there are even number of persons who shake hand exactly with an even number of persons
  • none of these

Key Concepts


Logic

Relations

Numbers

Check the Answer


Answer: there is at least one person who shakes hand with an even number of persons

B.Stat Objective Question 63

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


Let R be handshakes among 99 persons holds

first person may handshake with at most 98(even) other persons, for second person similar arguments hold and this holds with similar arguments for all persons

then there exists at least one person who shakes hand with an even number of persons.

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Box and ball Probability | B.Stat Objective TOMATO Problem 59

Try this problem from I.S.I. B.Stat TOMATO Objective Problem based on Box and ball Probability.

Box and ball Probability ( B.Stat Objective Problem )


A box contains 100 balls of different colours 28 red 17 blue 21 green 10 white 12 yellow 12 black. The smallest number n such that any n balls drawn from the box will contain at least 15 balls of the same colour is

  • 8
  • 77
  • 11
  • 10

Key Concepts


number Series

Logic

Integers

Check the Answer


Answer: 77

B.Stat Objective Problem

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints


28 -15 gives 13 and 17-15 gives 2 and 21 -15 gives 6 rest are less than 15

then 100 -13=77 and 100-2=98 and 100-6= 94

then smallest number= 77

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