Question

Of the three numbers, first is

twice the second and second is

twice the third. The average of

three numbers is 21. The smallest of the three numbers is

Answer 1

Let the first number be x
and the second number be y
and the third number be z

according to the condition
2x = y. (1)
2y = z. (2)

X + y + z
------------- = 21
3

X + y + z = 63

X + 2x + 2y = 63. ( from (1) and (2) )

3x + 2(2x) = 63

3x + 4x = 63

7x = 63

X = 63/7

X = 9

putting in equation (1)

2(9) = y

y = 18

putting in equation (2)

2(18) = z

z = 36

So the X is the smallest amongst them