Answer:
D
Step-by-step explanation:
-(-4)=+4
so it is -20+4
First, you add up the total number of students because we would base our percentage one this.
Total number of students = 1+4+5+10+20+10+5
Total number of students = 55
Now, let's count how many of them got a score of more than 70. For this, you would only count the students belonging to 70-under 80, 80-under 90 and 90-under 100.
Students who got more than 70 = 20+ 10 + 5 = 35
Therefore the percentage is equal to:
Percentage = 35/55 * 100 = 63.64%
