The ratio of the number of boys to the number of girls in a school of 640 students, is 5:3. If 30 more girls are admitted in the school, then how many boys should be admitted so that the ratio of boys to that of the girls, become 14 : 9
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e 20
Total girls in beginning = 640/8 × 3 = 240
& Boys in beginning = 640/8 × 5
= 400
Boys/Girls = (400 + x)/(240 + 30) = 14/9
⇒ (400 + x)/270) = 14/9
⇒ (400 + x)/30 = 14
⇒ (400 + x) = 420
⇒ x = 420 - 400
boys = 20