Question

([solve by writing an equation])

A pair of jeans costs 75% as much as a pair of corduroy pants. what is the cost of each if the total cost for the jeans and cords is $42?
I know the answer is Jeans: $18 and Cords: $24 but how do I write that in an equation to solve??
thank you!!!

Answer 1

Let the pair of jeans cost x dollars and the pair of corduroy cost y dollars.

"A pair of jeans costs 75% as much as a pair of corduroy pants."

this means
`x=(75)/(100)*y`, simplifying by 25:


`x= (3)/(4) y` (equation 1)


"the total cost for the jeans and cords is $42?"

x+y=42 (equation 2)

substitute x form equation 1, in equation 2

x+y=42


`(3)/(4) y+y=42`


`(3)/(4) y+ (4)/(4) y=42`


`7y=4*42`

y=4*6=24

substitute y=24 in either of equations 1 or 2:

x+y=42 (equation 2)
x+24=42
x=42-24=18

Answer: Jeans cost 18$, Cords cost 24$