Question

A pair of pants costs twice as much as a shirt. The total cost of 1 pair of pants and 1

shirt is $18. If s represents the cost of 1 shirt, which equation could you use to find the
cost of 1 shirt?

Answer 1

The equation, or more accurately, the system of equations we can use is:

x + y = 18

2x = y

Explanation:

Consider that the cost of the shirt was x.

Consider the cost of the pants to be y.

Then, you can say that 2x = y since twice the cost of the shirt would give you the cost of the pants which are represented by y.

The next piece of information can be used to form the equation x + y = 18 since the cost of a pair of pants and a shirt are, in total, $18.

We can use a system of equations to answer this.

2x = y

x + y = 18

Since y = 2x, use substitution.

x + 2x = 18

3x = 18 (Divide both sides by 3)

x = 6

x represents the cost of the shirt and thus, the shirt costs $6.

The equation, or more accurately, the system of equations we can use is:

x + y = 18

2x = y

Answer 2

2s+1s = 18

3s = 18

Since the question asks for the equation

Explanation:

Let s = cost of 1 shirt

Pants cost twice the price of 1 shirt

p = 2s

We are buying 1 pair of pants and 1 shirt for 18 dollars

2s+1s = 18

Combining like terms

3s = 18

Either equation can be used to solve

We can divide by 3 to solve for the cost of 1 shirt

3s/3 = 18/3

s = 6