The average weight of 20 students in a class is increased by 0.75 kg when one of the students weighing 30 kg is replaced by a new student. Weight of the new student (in kg) is :
Options:
A . 40
B . 35
C . 50
D . 45
Answer: Option D Answer: (d)Required answer = 30 + 20 × 0.75 = 30 kg + 15 kg = 45 kg Aliter : Using Rule 18, If in the group of N persons, a new person comes at the place of a person of 'T’ years, so that average age, increases by 't’ years Then, the age of the new person = T + N.t. Here, N = 20, T = 30, t = 0.75 Weight of New student = T + Nt = 30 + 20 × 0.75 = 30 + 15 = 45 kg
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