Final answer:
To solve for the number of T-shirts Sally can buy, the equation 30 + 15x = 75 is used. After deducting the purse's cost and dividing by the cost of one T-shirt, we found that Sally can purchase 3 T-shirts.
Step-by-step explanation:
The question involves coming up with an equation to solve for the number of T-shirts Sally can buy with the remaining money after purchasing a purse for $30. Since Sally spent a total of $75, we subtract the cost of the purse from this amount to find out how much she has left for T-shirts. If each shirt costs $15, then the number of T-shirts she can buy, represented by x, is equal to the leftover money divided by the cost per T-shirt. So, the equation is:
30 + 15x = 75
To solve for x, we first subtract 30 from both sides of the equation:
15x = 75 - 30
15x = 45
Then, we divide both sides by 15 to get:
x= 45 / 15
x = 3
Therefore, Sally can purchase 3 T-shirts with the remaining money.