A total of 60 students are traveling by bus. The ratio of the number of boys to that of girls is 2: 1. Then 15 boys get down and 5 girls get in the bus at the stop, and 5 boys get in and 10 girls get down from the bus at the second stop. What is the ratio of the number of boys to that of girls in the bus after the second stop?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 2: 1.
Total number of students = 60
The ratio of the number of boys to that of girls = 2: 1
Number of boys = 60 × (2 ÷ 3) = 40
Number of girls = 60 - 40 = 20
Then 15 boys get down and 5 girls get on the bus at the stop.
Then number of boys = 40 - 15 = 25
Number of girls = 20 + 5 = 25
Then 5 boys get in and 10 girls get down from the bus at the second stop.
The number of boys = 25 + 5 = 30
Number of girls = 25 - 10 = 15
The ratio of the number of boys to that of girls on the bus after the second stop = 30 : 15 = 2 : 1