Question

The average of five consecutive
odd numbers is 27. What is the
product of the first and the last
number?
(1) 621
(2) 667
(3) 713
(4) 725​

Answer 1

ANSWER:

• The product of first and the last number. = 713.

GIVEN:

• The average of five consecutive odd numbers is 27.

TO FIND:

• The product of first and the last number.

EXPLANATION:

Let the numbers be 2x + 1, 2x + 3, 2x + 5, 2x + 7, 2x + 9 [ As 2x is always even ]

Average = sum of n values / n

27 = (2x + 1 + 2x + 3 + 2x + 5 + 2x + 7 + 2x + 9) / 5

27 = 10x + 25 / 5

135 = 10x + 25

10x = 110

x = 11

First number = 2x + 1

First number = 2(11) + 1

First number= 22 + 1

First number = 23

Last number = 2x + 9

Last number = 2(11) + 9

Last number = 22 + 9

Last number = 31

Product = 23 × 31

Product = 713

Hence the product of first and the last number. = 713.