The average weight of M,N,O and P is 44 kg. A new person Q is also included in the group, then the average weight of the group is increased by 1 kg. Again a new person R is replaced M. Then the new average of 5 person becomes 46 kg. what is the average weight of N,O,P and R ?

M+N+O+P = 44 × 4 = 176 kg. Adding Q: average increases by 1 kg, so new average = 45 kg for 5 people. Total with Q = 45 × 5 = 225 kg. Q's weight = 225 - 176 = 49 kg. Replacing M with R: new average of 5 people = 46 kg. Total = 46 × 5 = 230 kg. Since Q stays, weight of (N+O+P+R) = 230 - 49 = 181 kg. Average of N,O,P,R = 181/4 = 45.25 kg.