To solve this you must use a proportion like so...
70 is a percent and percent's are always taken out of the 100. This means that one proportion will have 70 as the part and 100 as the whole
We know that there are 56 graphic T-shirts, but all the T-shirts are not graphic T-shirts. This means 56 is the part and the total number of T-shirts on sale (let's make this x) is the whole.
Here is your proportion:
Now you must cross multiply
56*100 = 70*x
5600 = 70x
To isolate x divide 70 to both sides
5600/70 = 70x/70
80 = x
This means that there are a total of 80 t-shirts on sale at the clothing store.
Hope this helped!
~Just a girl in love with Shawn Mendes