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ISI MStat 2015 PSA Problem 17 | Basic Inequality

This is a problem from ISI MStat 2015 PSA Problem 17. First, try the problem yourself, then go through the sequential hints we provide.

Basic Inequality - ISI MStat Year 2015 PSA Question 17


Let X=\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+\dots+\frac{1}{3001}. Then,

  • x<1
  • x>\frac{3}{2}
  • 1<x< \frac{3}{2}
  • None of these

Key Concepts


Basic Inequality

Check the Answer


Answer: is 1<x< \frac{3}{2}

ISI MStat 2015 PSA Problem 17

Precollege Mathematics

Try with Hints


Take it easy. Group things up. Use \frac{1}{n+k} < \frac{1}{n} for all natural (k)

\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+\dots+\frac{1}{1999} < 1000 \times \frac{1}{1000}
\frac{1}{2000}+\frac{1}{2001}+\frac{1}{2002}+\dots+\frac{1}{3001} < 1000 \times \frac{1}{2000}

\Rightarrow x < 1+ \frac{1}{2}= \frac{3}{2}

Again see that we can write , x=(\frac{1}{1001}+\frac{1}{3001}) + (\frac{1}{1002}+\frac{1}{3000})+ \dots + (\frac{1}{2000}+\frac{1}{2002}) + \frac{1}{2001} > \frac{2}{2001} +\frac{2}{2001} + \dots + \frac{2}{2001} +\frac{1}{2001} > \frac{2001}{2001}=1

Hence , 1<x< \frac{3}{2}.

Similar Problems and Solutions



ISI MStat 2015 PSA Problem 17
Outstanding Statistics Program with Applications

Outstanding Statistics Program with Applications

Subscribe to Cheenta at Youtube


This is a problem from ISI MStat 2015 PSA Problem 17. First, try the problem yourself, then go through the sequential hints we provide.

Basic Inequality - ISI MStat Year 2015 PSA Question 17


Let X=\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+\dots+\frac{1}{3001}. Then,

  • x<1
  • x>\frac{3}{2}
  • 1<x< \frac{3}{2}
  • None of these

Key Concepts


Basic Inequality

Check the Answer


Answer: is 1<x< \frac{3}{2}

ISI MStat 2015 PSA Problem 17

Precollege Mathematics

Try with Hints


Take it easy. Group things up. Use \frac{1}{n+k} < \frac{1}{n} for all natural (k)

\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+\dots+\frac{1}{1999} < 1000 \times \frac{1}{1000}
\frac{1}{2000}+\frac{1}{2001}+\frac{1}{2002}+\dots+\frac{1}{3001} < 1000 \times \frac{1}{2000}

\Rightarrow x < 1+ \frac{1}{2}= \frac{3}{2}

Again see that we can write , x=(\frac{1}{1001}+\frac{1}{3001}) + (\frac{1}{1002}+\frac{1}{3000})+ \dots + (\frac{1}{2000}+\frac{1}{2002}) + \frac{1}{2001} > \frac{2}{2001} +\frac{2}{2001} + \dots + \frac{2}{2001} +\frac{1}{2001} > \frac{2001}{2001}=1

Hence , 1<x< \frac{3}{2}.

Similar Problems and Solutions



ISI MStat 2015 PSA Problem 17
Outstanding Statistics Program with Applications

Outstanding Statistics Program with Applications

Subscribe to Cheenta at Youtube


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