Question

The sum of three numbers is 30. One of the numbers is 5 more than twice a second number and 5 less than the third number. What are the numbers?

Answer 1

Solution:

Let Ist no. = x

2nd no. = y

3rd no. = z

According to question x + y + z = 30 ...(1)

and x = 2y + 5 ... (2)

also x = z - 5 ...(3)

Hence 2y + 5 = z - 5 (By equation (2) & (3))

= z = 2y +5 + 5 = 2y +10 ... (4)

By putting equation (4) in (1) we get

= x + y + 2y + 10 = 30

From equation (2) x = 2y +5 ,put it in (1)

= 2y +5 + y + 2y + 10 = 30

= 5y = 15

= y = 3

By equation (2) ,x = 2y + 5 = 2×3 +5 = 11

By equation (4) ,z = 2y + 10 = 2×3 + 10 = 16

So x + y +z = 30

= 11 + 3 + 16 = 30