A washer and a dryer cost 821 combined. The washer costs 79 less than the dryer. What is the cost of the dryer?

Answer 1

You have 2 unknowns so you must have 2 equations to solve this.

Let x=cost of the washer

y=cost of the dryer

Eq. I: x+y=821

Eq. II x=y-79

Using the substitution method we can use the "value" of x from Eq. II in Eq. I and solve for y:

x+y=821 Eq. I

x=y-79 Eq. II

(y-79)+y=821 substitute for x

2y-79=821 simplify

2y=821+79 add 79 to both sides to isolate the y term

2y=900 simplify

y=900/2 divide both sides by 2 to isolate y

y=450 solve for y

Using this value for y in Eq. II we can solve for x:

x=y-79 Eq. II

x=450-79 substituting for 450 for y

x=371 solve for x

Check your answers in both equations:

Eq. I Eq. II

x+y=821 x=y-79

371+450=821 371=450-79

821=821 371=371

Check Check

Both answers check in both equations, so we know that the answers are correct. Therefore, the cost of the washer is 371 and the cost of the dryer is 450.

Hope this helps! Happy New Year!!

Answer 2

Let W = cost of washer

Let D = cost of dryer

eq.1 W + D = 821

eq. 2 W = D-79

Substituting eq.2 into eq.1, you get D-79 + D = 821

2D-79 = 821

2D = 821 + 79

2D = 900

D = 450

So the dryer cost $450

(and the washer would cost $371, which is $79 less than the dryer)