SAT Math: Central Tendency 3

1. A teacher recorded her students' assessment grade (scored out of 10) in the table below.

If the average score was an 8, how many of her students received a score of 9?

$7$

$8$

$9$

$10$

2. 280 students from a local high school participated in a summer internship program. The average amount earned in a day by 30 freshman were $45, $54 by 50 sophomores, $72 by 70 juniors, and $81 by 130 seniors. What were the average earnings in one day for the combined groups?

$\$ 63$

$\$ 70$

$\$ 75$

$\$ 81$

3. Anya has grades of 88, 73, and 70 on three math tests. What grade must she receive on the next test to have an average of 82?

$77$

$84$

$97$

$100$

4. The table below shows the score (out of 25) that Mary's 12 firends have achieved in a carnival fair game.

Mary is the last person to play. Her score increases the team's average score by one point, but doesn't change the median. What is Mary's score?

5. 6 is both the mean and median in a set of five positive integers. The mode of the set is 10. What is the difference between the largest and smallest integers in the set?

6. Nicole works as a waitress, and she keeps track of the tips she earns. After work on Thursday this week, she notes that her average (arithmetic mean) tip total for Tuesday, Wednesday, and Thursday is $85. How much would Nicole have to earn in tips on Friday and Saturday, in total, to bring her 5-day average tip to $100?