Answer:
Richard got a 90% score on his quiz! Therefore, he got 10% of the questions incorrect.
Explanation:
The method I used to find this answer was simply taking the amount he had gotten, 36, and dividing it by the initial amount of questions- 40. From there, I got 0.9, which is the equivalent of 90%. 100% minus 90% is 10%, so he got 10% incorrect. Sorry for the mishap, I didn't pick up that it was meant to be the amount incorrect. :)