Answers

2016-05-06T12:14:24+05:30
Let the total no.of students be 'x'.
then 50% of x=x/2
1/20 of x=x/20
1/10 of x =x/10
remaining 70 students .
now we have ,
x/2=x/20+x/10+70
LCM of 20 and 10=20
x/2={(x+2x)/20}+70
x/2=3x/20+70
x/2=(1400+3x)/20
20x=2{(1400+3x)}
20x=2800+6x
20x-6x=2800
14x=2800
x=2800/14
x=200.
number of 10 year old students are = x/20
=200/20
=10.
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