John buys 3 dress shirts. They sell for $20 each. He also has to pay 10% tax on everything. How much did he pay in total?
Stream of thoughts:
66
The shirts cost 3 * $20 = $60 before tax.

The tax cost $60 *.

1 = $6.

So in total they paid $60 + $6 = $66.

.

Thus, the answer is 66