The <u><em>correct answer</em></u> is:
15 weeks
Explanation:
Let w be the number of weeks. Bill weighs 150 pounds and wants to gain 2 lbs per week; this gives us the expression 150+2w for Bill.
Jamal weighs 195 and wants to lose 1 pound per week; this gives us the expression 195-1w for Jamal.
To determine how many weeks it will take them to weigh the same, we set the two expressions equal:
150+2w=195-1w
Add 1w to each side:
150+2w+1w = 195-1w+1w
150+3w = 195
Subtract 150 from each side:
150+3w-150 = 195-150
3w = 45
Divide each side by 3:
3w/3 = 45/3
w = 15
Lets say your numbers are these...
10,20,30,40,50,60,70,80,90 and 100
you would add those to get 650
Now how many numbers did you add?
You added 10
so now divided
650 by 10
you get 65
that is the mean of those numbers!