The average weight of A, B, C and D is 33 kg. C is 12 kg lighter than A, while B is 6 kg heavier than C. D's weight is 10 kg less than that of C. What is the average weight of A and D?

32 kg

Sum of weight of A , B , C & D = 4 × 33 = 132 kg

A + B + C + D = 132  ----(1)

Let weight of C = C kg

So , Weight of A = C + 12 , Weight of B = C + 6 , Weight of D = C - 10

Put in equation 1

C + 12 + C + 6 + C + C - 10 = 132

4C + 8 = 132

4C = 124

C = 31

Weight of A = 31 + 12 = 43 kg , Weight of D = 31 - 10 = 21 kg

Average weight of A & D = \(\frac{43 + 21 }{2}\) = \(\frac{64}{2}\) 

= 32 kg