Half of the students in a calss are girls.if the number of boys was twice as large and the number of girls half as large,what would the percentage of boys in the calss become?
问题描述：
Half of the students in a calss are girls.if the number of boys was twice as large and the number of girls half as large,what would the percentage of boys in the calss become?
答
80%
现在男女数量一样.设 # boys = # girls = x.
如果男孩数量翻倍,那么#boys= 2*x=2x
女孩数量减半,那么#girls=0.5*x = 0.5x
男孩percentage（百分比）就是2/(2+0.5)*100% = 2/2.5*100%=80%