Question

the average of five consecutive even numbers is 90 . What will be the product of the smallest and the greatest number of them
1)7740
2)9000.
3)8084.
4) None of these​

Answer 1

Step-by-step explanation:

Assume the least number in the set of even integers to be x. So, the equation is

x + (x + 2) + (x + 4) + (x + 6) + (x + 8) = 90 x 5 = 450

or 5x + 20 = 450, or 5x = 430, or x = 86.

So the greatest is x + 8 = 94.

Therefore, the least number in the odd sequence = 94 + 15 = 109.

So the odd sequence is 109, 111, 113, 115, 117.

In any evenly spaced odd-numbered sequence (as in this case: diff. between successive numbers is 2, number is 5), the number in the middle gives the average of the sequence. So, the required number is 113.

Cross-check: (109 + 111 + 113 + 115 + 117)/5 = 565/5 = 113.