In a class of 60, where girls are twice that of boys , Kamal ranked seventeenth from the top . If there are 9 girls ahead of Kamal , how many boys are after him in rank ?

Created: 6 years ago |

Bangladesh Bank Bangladesh Bank - Assistant Director - 2016 গণিত সম্ভাব্যতা (Probability)

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Best Ans:

Q. In a class of 60, where girls are twice that of boys , Kamal ranked seventeenth from the top . If there are 9 girls ahead of Kamal , how many boys are after him in rank ?

Let, No. of boys = x
As per question,
x + 2x = 60
∴ x = 20

∴ No. of boys = 20 and No. of girls = 40

As Kamal ranked 17th from the top, so there are 16 students ahead of him (including 9 girls).
that means, there are 7 boys and 9 girls ahead of Kamal.

Now, till 17th there are (7 boys + Kamal) = 8 boys
So, remaining boys that ranked after Kamal = (20-8) = 12 boys (Ans:)