**Problem : ** What is the mean average of
{13, 15, 19, 13}
?

**Problem : ** What is the mean average of
{7, 12, 3, -2, -4, 14}
?

**Problem : ** What is the mean average of
{4, 13, 0, -12, -2, 21, -17}
?

**Problem : ** What number must be added to the set
{2, 6, 12, 0}
to yield an average of 6?

**Problem : ** What number must be added to the set
{7, -7, 15}
to yield an average of -5?

**Problem : ** Jonah receives the following scores on his biology tests:
{95, 99, 92, 89}
.

a) If
100
is the highest grade possible on a test, and there is one test left, what is the highest average Jonah can get?

b) What is the minimum score he needs on the final test to get an A (at least
90
average) in the class?

b) 75

**Problem : ** Kat receives the following scores on her chemistry tests:
{88, 92, 74, *x*, 94, 85}
.

a) If
*x* = 80
, what is Kat's average?

b) If Kat's average is
83
, what is
*x*
?

c) If the highest possible score on a test is
100
, can Kat get a
90
in the class?

b)

c) No, she cannot get higher than an 88.8 (she would need a 107 on the fourth test to get a 90).