mean marks of boys and girls are70and72 respectively. if mean of all students is71. find rates ofno.of boyes to no.of girls.
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total marks obtained by boys be x and total boys are y
total marks obtained by girls be a and total girls be b
x/y=70
a/b=72
(x+a)/(y+b)=71
x+a=71y+71b
since x=70y and a=72b
so
70y+72b=71y+71b
b=y
ratio of boys to girls is
y/b=1
so 1:1
total marks obtained by girls be a and total girls be b
x/y=70
a/b=72
(x+a)/(y+b)=71
x+a=71y+71b
since x=70y and a=72b
so
70y+72b=71y+71b
b=y
ratio of boys to girls is
y/b=1
so 1:1
sahanajbibi:
how are you
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