math question (need assistance)

Question

An animal shelter spends $2 per day to care for each cat and $5 per day to care for each dog. Mr. Morine noticed that the shelter spent $67 caring for cats and dogs on Wednesday. Later, Pat found a record showing that there were a total of 20 cats and dogs at the shelter on Wednesday. How many cats were at the shelter on Wednesday?

Answer 1

2c + 5d = 67

c + d = 20 Rewrite as c = 20 - d

2(20-d) + 5d = 67

40 - 2d + 5d = 67

40 + 3d = 67

3d = 27

d = 9

c + 9 = 20

c = 11

11 cats and 9 dogs. 22+45 = 67 ■