In a class, ratio of the boys to the girls is 5:3. If 20% of the boys and 40% of the girls fail an exam, what is the ratio of the number of boys who passed to the number of girls who passed?
Show answer & explanation
Correct answer: A
Explanation
Given:
Boys : Girls = 5 : 3
20% of boys failed
40% of girls failed
Formula:
Passed = Total − Failed
Let
Boys = 5x
Girls = 3x
Boys who passed = 80% × 5x
= (80/100) × 5x = 4x
Girls who passed = 60% × 3x
= (60/100) × 3x = 1.8x
Ratio = 4x : 1.8x = 40 : 18 = 20 : 9
Boys who passed = Girls who passed = 20 : 9