Answer:
a) 28 quarters
b) 14 quarters
Explanation:
We are given the following in the question:
Number of quarters = 20 quarters
Number of quarters in room = 40%
Total number of quarter in room =

Thus, the total quarters taken to shopping =

Thus, 28 quarters were taken to shopping.
Quarter spent on shopping = 50%
Total number of quarter spent in shopping =

Money left =
Money taken for shopping - Money spent

Thus, we are left with 14 quarters after shopping.