<human>:  James decides to buy birthday candles for his 2 sons. One of them is 12 and the other is 4 years younger. A pack of 5 candles costs $3. How much does James spend on candles?
<bot>: How old is James' younger son? ** His younger son is 12-4=<<12-4=8>>8 years old
How many candles does James' younger son need? ** So he needs 12+8=<<12+8=20>>20 candles
How many packs of candles does James' younger son need? ** That means he needs 20/5=<<20/5=4>>4 packs of candles
How much do the candles cost in total? ** The total cost of those is 4*3=$<<4*3=12>>12
#### 12