Saturday, 6 July 2013

find the number of boys and girls

The number of boys and girls are in the ratio of 7:5 . The number of boys is 8 more than girls.Find the number of boys and girls ?

answer - Let the common multiples of boys and girls be 7x and 5x
number of girls = 5x
number of boys = 7x + 8
according to condition
7x - 5x = 8
2x = 8
x = 8/2
x = 4
number of boys = 7 X x = 7 X 4 = 28
number of girls = 5 X x = 5 X 4 =  20
-------> number of boys is 28 and number of girls is 20

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