Answer:
The probability that a student makes more than 15 mistakes is 21% or 0.21
Explanation:
To get the probability of making more than 15 mistakes we have to use the information of the others possibilities
Probability A=Probability of making 7 mistakes on the exam is 0.21
Probability B= Probability that a student makes from 7 to 15 (inclusive) mistakes is 0.58.
Probability C=The other option is making more than 15 mistakes.
We consider we have only those 3 options so they have to make the 100%
3 options =100%= probability A + Probability B+ Probability C
Then, Probability C= 100%-probability A - Probability B
Probability C= 100%-21% - 58%
Probability C= 21%