解:设这个数为x 根据题意得
75%x=30*25%+1.5
75%x=7.5+1.5
75%x=9
x=9\75%
x=12
(30x25%+1.5)÷75%
=(30x0.25+1.5)÷0.75
=30x0.25÷0.75+1.5÷0.75
=10+2
=12
谢谢,请采纳
75%x-30X25%=1.5
0.75x=1.5+7.5
x=9÷0.75
x=12
(30×25%+1.5)÷75%
=(7.5+1.5)÷75%
=9÷75%
=12
75%x-30*25%=1.5
x=12