Laurie was completing the treasurer's report for her son's Boy Scout troop at the end of the school year. She didn't remember how many boys had paid the $24 full-year registration fee and how many had paid a $16 partial-year fee. She knew that the number of boys who paid for a full-year was ten more than the number who paid for a partial-year. If $400 was collected for all the registrations, how many boys had paid the full-year fee and how many had paid the partial-year

14 boys paid for the full year fee and 4 boys paid for the partial year fee

Step-by-step explanation:

Create a system of equations, where x is the number that paid for the $24 fee and y is the number that paid for the $16 fee:

24x + 16y = 400

x = y + 10

Solve by substitution by plugging in y + 10 as x:

24x + 16y = 400

24(y + 10) + 16y = 400

Solve for y:

24y + 240 + 16y = 400

40y + 240 = 400

40y = 160

y = 4

Then, plug in 4 as y to find x:

x = y + 10

x = 4 + 10

x = 14

So, 14 boys paid for the full year fee and 4 boys paid for the partial year fee.

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0

because they could drop even lower..