Average of weights of Mike and Susan is 35 kg. Average of weights of Mike and Ashley is 40 kg. Average of weights of Ashley and Susan is 45 kg. How much is the weight of Susan?

**(A)** 35 kg

**(B)** 37.5 kg

**(C)** 40 kg

**(D)** 42.5 kg

**(E)** None of the above

Let weight of Susan = S

Let weight of Mike = M

Let weight of Ashley = A

It is given to us that kg

**(1)**

It is also given to us that kg

**(2)**

Subtracting equation **(1)** from **(2)**, we get

**(3)**

It is also given to us that kg

**(4)**

Subtracting equation **(3)** from **(4), **we get

**kg**

Hence, the answer is **(C)**.