NDA2019MathematicsBasics of MathematicsActual
The mean weight of 150 students in a certain class is 60 kg . The mean weight of boys is 70 kg and that of girls is 55 kg . What are the number of boys and girls respectively in the class?
Options
- A75 and 75
- B50 and 100
- C70 and 80
- D100 and 50
Correct answer
B. 50 and 100
Step-by-step solution
Let no. of boys be x . aligned & 60= 70 x+55(150-x) 150 & 15 x+8250=9000 & 15 x=750 & x=50 & Boys =50 and girls =100 . aligned