Answer:
66
Step-by-step explanation:
Use the formula for the mean of a set of numbers:
sum of the numbers
average = --------------------------------
count of numbers
Here we know that the average mark was 68, so we can write:
75 + 62 + 84 + 53 + x
average = 68 = ----------------------------------
5
or 274 + x
68 = -------------------
5
Solving for x, we multiply both sides by 5: 340 = 274 + x.
Subtracting 274 from both sides effectively isolates x:
340 = 274 + x
- 274 -274
------------------------
66 = x
The fifth student's mark was 66.
Answer:
Anylize the results
Step-by-step explanation:
9514 1404 393
Answer:
a8 = 4
Step-by-step explanation:
Put 8 where n is and do the arithmetic.
a8 = (1/2)(8) = 8/2 = 4
The 8th term of this arithmetic sequence is 4.