Explanation
In order to find Katie’s savings after six months, it is first necessary to compute her monthly savings. Her monthly savings depend on her income and her tax rate. Begin by finding the amount of after-tax income:
After tax income =S−S(0.25)
After tax income =0.75S
Of this amount, Katie saves 20%:
0.75S∗0.20=0.15S
Multiply Katie’s monthly savings by 6 to calculate the amount of savings after six months:
0.15S∗6=0.9S