Question

The average weight of Arya, Ben and Chris is 45 kg. If the average weight of Arya and Ben be 40 kg and that of Ben and Chris be 43 kg, what is the weight of Ben?

• A. 30
• B. 32
• C. 31
• D. 33
• E. 34

Answer 1

The correct option is C

31

Let, the weight of Arya, Ben and Chris be a, b and c respectively.

Average weight of Arya, Ben and Chris = a + b + c=45$\times$3=135 --- equation (1)

Average weight of Arya and Ben =a + b=40$\times$2=80---equation (2)

Average weight of Ben and Chris =b + c=43$\times$2=86---equation (3)

equation (2) + equation (3) - equation (1)

$\Rightarrow$ a + b + b + c - (a + b + c) = 80 + 86 - 135

$\Rightarrow$ b = 80 + 86 -135 = 166 - 135 = 31

$\Rightarrow$Weight of Ben = 31 kg