You have to make a part over whole proportion (
![(part)/(whole)=(part)/(whole)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/sc8pdl8ev5uq1hthgwkq6vpner3v429tfs.png)
One fraction will be the unknown percent over 100 (the "whole" of all percents are always 100)
The other fraction will be cost of books over total education cost (
![(400)/(1300)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/d50wr7olg80mtpv8p45b3hv8pkg5oo7bqd.png)
Proportion:
![(400)/(1300)=(x)/(100)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qldjd4tepiu7w48fmq1xl0lxyojxmssjov.png)
Now cross multiply
400 * 100 = 1300 * x
40000 = 1300x
Solve for x by dividing 1300 to both sides
40000/13000 = 1300x/1300
x = 30.76923
I will round to the nearest tenth...
30.8% is the percent spent on books
Hope this helped!
~Just a girl in love with Shawn Mendes