Answer:
She got 10% of the questions wrong !
Explanation:
To solve this problem I used cross multiplication
![(x)/(100)= (18)/(20)](https://img.qammunity.org/2021/formulas/mathematics/high-school/y9oojppjprxdvmvrfnaius65xgr75cou6v.png)
18 x 100 =1800
1800 / 20 = 90
Since they are asking what she got wrong, not what she got right, you just need to subtract.
100% - 90% = 10%
hope this helped !