John buys 20 candy bars.  His brother Dave pays for 6 of them.  If each candy bar costs $1.50, how much did John pay?
How many candy bars did John pay for? ** He paid for 20-6=<<20-6=14>>14 candy bars
How much did John pay? ** So he paid 14*1.5=$<<14*1.5=21>>21
#### 21