Math, asked by raghav149, 1 year ago

in a class of 60 where girls are twice that of boys Amal ranks 17th from the top if there are 9 girls ahead of Amal how many boys are after him in rank

Answers

Answered by Adityaadidangi
0
girls are40 and boys are 20 as total are 60 students
Amal ranks 17th, so 16 are before him
if 9 are girls then remain 7 are boys
total are 20 boys
then 12 boys are after him as 9 girls and 7 boys are before him

raghav149: plzz expalin
Adityaadidangi: is it clear
Answered by apoorvas763p7iys9
0
1-16
17th
18-6

If before Amal (17th from top) ,9 girls are there, So,no. of boys ahead of Amal is 16-9=7
Now, let us assume total no. of girls- x
told no of boys in class-y
so,x+y = 60...(1)
now let us assume no of girls behind Amal is z and no. of guys behind Amal is a
so ,z+a = 43...(2)
and ,
Also, according to ur questions,total no. of girls are twice the no. of boys i.e.
x= 2y...(3)
substituting 3 in 1
2y+y = 60
3y =60
y = 20...so,x=40

if 9 girls are ahead of Amal and tolal no. of girls are 40..so,no. of girl behind him is 31 (z)
substituting this value in eq(2)
31+a= 43
a=43-31= 12
So,no. of boys behind Amal are 12
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