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).
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