Question

解方程300×20%+X=(300+x)×40%

Answer 1

300×20%+X=(300+x)×40%
300×20%+X=300×40%+40%x
60+x=120+0.4x
x-0.4x=120-60
0.6x= 60
x = 60÷0.6
x = 100