Question

Ted needs an average of at least 70 on his three history tests. He has already scored 85 and 60 on two tests. What is the minimum grade Ted needs on his third test?

Answer 1

To find the mean you must add up all the numbers and divide by how many there are:
35 + 60 + x
_________ = 70
3

35 + 60 + x = 210

x = 65

He must score at least a 65 for a 70 average.

Answer 2

Minimum grade Ted needs on his third test is:

65

Explanation:

Ted scored 85 and 60 on two tests.

Ted needs an average of at least 70 on his three history tests.

Let he scored x in third test

So,

`(85+60+x)/(3)\geq  70`

Multiplying both sides by 3, we get

85+60+x ≥ 70×3

145+x ≥ 210

subtracting both sides by 145, we get

x ≥ 65

Hence, minimum grade Ted needs on his third test is:

65