Please answer below :-)

B. 88.8

Step-by-step explanation:

let x represent class y

(x+71.2)/2=80   multiply each side by 2

x+71.2=160      subtract 71.2 by both sides

x=88.8

or

trial an error

replace x with each of the numbers and see if it plugs in.

example:

(80.5+71.2)/2=80

151.7/2=80

75.85=80?

false. incorrect

another example:

(88.8+71.2)/2=80

160/2=80

80=80?

true. correct

$450.00 for 6 weeks

or

$300

step-by-step explanation:

$200.00 for first week $50.00 x5 equals $250 plus $200 equals $450.00 for six weeks.

$200 for first week

$200 x 0.10 = $20

$20 x 5 = $100

$200 + $100 = $300

9 x 8 divided by (5-3)=36