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

Series and Integers (B.Stat Objective)

The value of \(\sum ij\), where the summation is over all i and j such that \(1 \leq i \lt j \leq 10\)

  • 2640
  • 1320
  • 3025
  • none of these

Key Concepts




Check the Answer

But try the problem first…

Answer: 1320

Suggested Reading

B.Stat Objective Question 81

Challenges and Thrills of Pre-College Mathematics by University Press

Try with Hints

First hint

required sum=1(2+3+4+….+10)+2(3+4+….+10)+3(4+5+….+10)+4(5+6+….+10)+5(6+7+….+10)+6(7+8+..+10)+7(8+9+10)+8(9+10)+9(10)

Second Hint


Final Step


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