On a certain exam, Tony corrected 20 papers and found the mean for his group to be 70. Alice corrected the remaining 10 papers
1 answer:
Answer:
The mean of the combined group is 76.67 ≈ 77
Step-by-step explanation:
- The sum of the grades in Tom's group is 20×70 = 1400
- The sum of grades in Alice's group is 10×90=900
- The sum of gradees in the combined group is =1400+900=2300
- Then the mean grade of the combined group is
where
- 2300 is the sum of the all grades in the combined group
- 30 is the total number of people in the group
You might be interested in
Given:
h(t) = 25 - a·t²
h(0.5) = 21
Find:
t such that h(t) = 0
Solution:
h(0.5) = 25 - a·0.5² = 21
25 - 21 = a/4
4·4 = a = 16
Then
h(t) = 25 - 16t²
We want h(t) = 0, so
0 = 25 - 16t²
16t² = 25
t² = 25/16 = (5/4)²
t = 5/4 = 1.25
It takes 1.25 seconds for the entire 25 ft drop.
h(t) = 25 - a·t²
h(0.5) = 21
Find:
t such that h(t) = 0
Solution:
h(0.5) = 25 - a·0.5² = 21
25 - 21 = a/4
4·4 = a = 16
Then
h(t) = 25 - 16t²
We want h(t) = 0, so
0 = 25 - 16t²
16t² = 25
t² = 25/16 = (5/4)²
t = 5/4 = 1.25
It takes 1.25 seconds for the entire 25 ft drop.