Mary must save a total of $390 for a new appliance. She has saved 2/3 of the amount. How much more money does she need to save for the appliance?

1 Answer
Dec 11, 2016

She needs to save $130 more.

Explanation:

First, we need to determine how much Mary has saved.

She has saved #2/3# of $390. The word "of" means to multiply.

And let's call how much Mary has saved #s#.

Then:

#s = 2/3 xx $390#

#s = 2 xx ($390)/3#

#s = 2 xx $130#

#s = $260#

Now let's call how much she needs #n#. The formula for calculating #n# is:

#n = c - s# where #c# is the total cost and #s# is how much is saved. We know the cost is$390 and we know Mary has saved $260 so we can write:

#n = $390 - $260#

#n = $130#