What is the "row heading" of the third row (marked with the question mark) in the table shown below?

    4 :  6, 11,  7
    3 :  8,  4, 12
    ? : 10, 55, 15

Explain the scheme used.

We observe that:
(6+11+7) = 24 = 6*4
(8 + 4 + 12)= 24 = 8*3

Hence, the sum of the second, third and fourth numbers in a row
= product of the first and the second numbers

Let the missing number be x.

Then,
10x = 10 + 55+ 15 = 80,  so that x = 8

Hence the required number is 8.

Edited on February 6, 2009, 3:28 pm

Posted by K Sengupta on 2007-03-30 04:58:32