How much does one shirt and one pair of pants cost?

Question

Matthew and Lindsey are buying new Christmas outfits. Matthew buys 3 shirts and 4 pairs of pants and pays $30. Lindsey buys 5 shirts and 4 pairs of pants and pays $40. Let s represent the costs of shirts and p represent the cost of pants

PLEASE HELP

Answer 1

Hi Ella I'm Eddie. This is a common type of problem so remember overall setup.

You must make 2 equations use letters/variables make sense so p (pants) and s (shirts).

Matthew Equation 3s + 4p = $30

Lindsey Equation 5s + 4p = $40

Notice I lined them up simply make bottom negative or muliply -1 both sides like below and add to solve.

Matthew Equation 3s + 4p = $30

Lindsey Equation -5s - 4p = -$40

Answer -2s + 0p = -$10 -2s = -$10 = $5 = s

2 2

It does not matter which is negative but one variable/letter must be the same like 4p but sometimes this requires multiplying by a number other than -1.

Now to solve for p (pants) simply plug to one of the original equations.

3s + 4p = $30 so 3($5) + 4p = $30 $15 + 4p = $30

-$15 -$15

0 + 4p = $15 p = $15 = $3.50

4 4 4

So p = $3.50 & s = $5 . Remember this set up many times ask this type of questions various ways. If your interested in further help I offer free first session.