Ryan is correct, the mean is about 8.1.
To find the mean, you have to add up all the values, then divide by the total amount.
For Sample A:
60 x 6 + 90 x 7 + 145 x 8 + 150 x 9 + 55 x 10 = 4050
If you add up all the adults, you have 500.
Dividing 4050 by 500 = 8.1
Sample B will produce a very similar result.
3 apples weigh 1 lb.....so 1 apple would weigh 1/3 = 0.3 lbs
If 450 is 1/4 of the amount that Henry has, you can find Henry’s amount by multiplying 450 • 4 which gives you an answer of 1800
Or, if you’re looking for a more complicated way, which I doubt, you can set up the problem as:
1/4x=450 and solve by dividing 450 by 1/4