Answer: she bought 13 petunias
Step-by-step explanation:
Let x represent the number of Petunias pot of flowers that she bought.
Let y represent the number of begonias pot of flowers that she bought.
She bought 22 potted plants. This means that
x + y = 22
Petunias cost $7 per pot and begonias cost $8 per pot. She spent a total of $163. This means that
7x + 8y = 163 - - - - - - - - - - - -1
Substituting x = 22 - y into equation 1, it becomes
7(22 - y) + 8y = 163
154 - 7y + 8y = 163
- 7y + 8y = 163 - 154
y = 9
x = 22 - y = 22 - 9
x = 13