Level 2
Benny swam for 3 days. On each day, he would do 2 more laps than the previous day. He did y number of laps on the first day. What was the total number of laps he did for the 3 days? Give your answer in terms of y.
Level 3
Irene has enough flour to bake either 21a tarts or 18 biscuits. If she has finished baking 5a tarts and 6 biscuits, how many more tarts can she still bake in terms of a?