The mean weight of 150 students in a certain class is 60 kg. The...

The mean weight of 150 students in a certain class is 60 kg. The mean weight of boys in the class is 70 kg and that of girls is 55 kg. What is the number of boys in the class?

Options

A50
B55
C60
D100

Correct answer

A. 50

Step-by-step solution

Number of students = 150
By aligation, ratio

=1: 2\therefore

No. of boys

=\frac{1}{3} \times 150=50

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