the ratio of the number of boys to girls in a school of 720 students is 3:5. if 18 new girls admitted in the school, find how many new boys may be admitted so that the ratio of the number of boys to number of girls may change to 2:3.
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Step-by-step explanation:
b:g = 3:5
b =3x, g=5x
total = 5x+3x = 8x =720
x =720/8 =90
b= 3×90 = 270
g = 5×90 =450
new no. of girls =g1, no. of boys =b1
no. of boys admitted =x
g1 = g+18 = 450 +18 = 468
b1 = b+x = 270+x
b1:g1 =270+x : 468 = 2:3
270+x = 2/3 ×468 = 2×156 = 312
270+x =312
x= 312 -270 = 42
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