Answer:
10
Step-by-step explanation:
Answer:

Step-by-step explanation:
we know that
The formula to find the sum is equal to

where
a1 is the first term
an is the last term
n is the number of terms
In this problem we have



substitute the values in the formula

Answer:
<u>Number of students:</u>
<u>Total of marks:</u>
- 5*6 + 4*7 + 7*8 + 10*9 + 4*10 = 244
<u>Mean mark:</u>