We are told that the expression
![60+20x](https://img.qammunity.org/2023/formulas/mathematics/high-school/ebzgsx54iglw5ss2bnl2ljl1xafc4fsf7t.png)
represents the total cost of the transaction. The problem tells us that the customer purchased a single pair of yeans and an indeterminate amount of shirts. We also know that each shirt costs the same amount.
Since we know that they purchased various shirts at the same price, the total cost of the shirts is an unknown number times the price of the shirt. In the expression given, the only multiplication is 20*x, so 20x must be the total cost of the shirts.
Since they only bought a pair of jeans, and the only remaing part of the expression is 60, 60 must be the cost of the jeans.