Question

A, b, c and d are four consecutive even numbers respectively and their average is 65. what is the product of a and d

Answer 1

x, x+2,x+4, x+6 / 4 = 65
4x+12 = 260 
4x = 248
x = 62

62 * 68 = 4216

Answer 2

The product of a and d is 4216.

This can be either done orally or using a variable 'x'.

1st method:

If the average is 65, therefore it should be located in the middle of the series. So the four consecutive even numbers are considered to be 62,64 and 66,68( since 65 is an odd number we do not consider that).

2nd method:

Let the first number be x

So the next 3 consecutive even numbers are:

x, x+2,x+4, and x+6

As we know, (x, x+2,x+4, and x+6)/ 4 = 65

So, 4x+12 = 260

or, 4x = 248

Hence,x = 62

So the value of a is 62 and d is 68 and their product is 4216.