arithmetic - the average weight of p q and r is 37 kg if the average weight of p and q be 33 kg and that of q and r be 42 kg then the weight of r is - skillgun

Let P, Q, R represent their respective weights. Then, we have:
P + Q + R = (37 x 3) = 111 .... (i)
P + Q = (33 x 2) = 66 .... (ii)
Q + R = (42 x 2) = 84 ....(iii)
Adding (ii) and (iii), we get: P + 2Q + R = 150 .... (iv)
Subtracting (i) from (iv), we get : Q = 39.
Q's weight = 39 kg.
R's weight = 84 - 39 = 45 kg.