The ratio of the number of boys to the number of girls in a class 4 : 15. The average height of the boys is 161.2 cm, and the average height of all the students is 154.5 cm. What is the average height ( in cm) of the girls? (Correct to one decimal place)
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 152.7.
Let boys = 4x, girls = 15x → Total = 19x
Total height all boys and girls = 154.5 × 19x = 2935.5x
Total height of boys = 161.2 × 4x = 644.8x
Total height of girls = 2935.5x - 644.8x = 2290.7x
Average girls height = 2290.7x/15x = 152.713... ≈ 152.7 cm