Answer:
5
Step-by-step explanation:
Let P be the number of quarters in a coin collection.
Seven times the number of quarters in a coin collection is expressed as;
7×P
= 7P... (1)
Also three times the number of quarters can be expressed as 3P. If this value is increased by 20, the resulting expression will be;
3P+20 (increment means addition)...(2)
If the two expression are the same then equation 1 = equation 2 i.e
7P = 3P + 20
7P-3P = 20
4P = 20
P = 20/4
P = 5
Therefore the number of quarters in the coin collection is 5