A local school is holding a fundraising event. everyone that attends receives a raffle ticket. at the end of the night the raffle is held. assume 1,000 people attend the event, and hence there are 1,000 tickets in the raffle. There will be

95 tickets that each win $10
45 tickets that each win $20
20 tickets that each win $50
10 tickets that each win $100
and the rest of the tickets win nothing

What is the variance of the winnings from this raffle?

the variance of the winnings from this raffle is 162.7

Step-by-step explanation:  

Given that;

X             P( X=x )        xP(x)         x²P(X)

10              0.095        0.95           9.5

20             0.045        0.9             18

50             0.020         1.0             50

100            0.010         1.0             100

0                0.830        0.0             0

TOTAL        1               3.85          177.5

therefore the variance will be;

Var(X) = [ ∑(x²) - [∑(X)]² ]

so we substitute

Var(X) = [ 177.5 - (3.85)² ]

= [ 177.5 - 14.8225 ]

=  162.6775  ≈ 162.7

therefore the variance of the winnings from this raffle is 162.7

squares, rhombus, rectangles

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9