math
posted by Anonymous .
Donovan spent some money on friday. He spent thrice as much money on saturday than on friday. He spent $20 on sunday. If he spent a total of $125 in the 3 days, how much did he spend on saturday?

x = money spent on Friday, thus 3x = money spent on Saturday.
x + 3x + 20 = 125
Solve for x and then 3x.