Answer:
One: 58.5
Two 36.6
Step-by-step explanation:
One
20 students * 65 = 1300 This is the total score of all 20 students. They may not all get 65, but 1300 is what their average total is.
20 students * 52 = 1040
The total score of all 40 students was 1300 + 1040 = 2340
The average for the entire class was 2340 / 40 = 58.5
Two
This question is done almost the same way.
Supposes the total number of members is 100. That means that 28 of them are men
28 * 33 = 924 This is the total age for the men
100 - 28 = 72 Out of 100, 72 of the people there are women.
72 * 38 = 2736
The total number of years of all of the members is
924 + 2736 = 3660
The average age of all members is 3660/100 = 36.6
Why did I pick 100 as the total membership? It is because a percentage is number out of 100. Am I allowed to invent things like that? Sure. I'm just using the definition of a percentage.
The average will make it come out the same.
