设黄球有x个,红球比黄球多50%,所以红球有(1+50%)x个,由题
(1+50%)x * 50% ÷20% = 30*2
3.75x = 60
x = 16
答:黄球有16个
算术的话是:
30×2=60
60×20%=12
12÷50%=24
24÷(1+50%)=16个
设黄球有x个,红球比黄球多50%,所以红球有(1+50%)x个,由题
(1+50%)x * 50% ÷20% = 30*2
3.75x = 60
x = 16
答:黄球有16个
算术的话是:
30×2=60
60×20%=12
12÷50%=24
24÷(1+50%)=16个