Samuel orders a video game online for $40.00. He has a 20% discount code, and the sales tax is 9%. What is the total cost of his order?

$34.88

Step-by-step explanation:

If the discount is 20%, then the sale price is 80% of the full (original) cost:

0.80($40.00) = $32.

Sam has to pay 9% sales tax on this $32.  The total cost of his order would then be 1.09($32) = $34.88.  If desired, you could write this as the equivalent $32 + 0.09($32).

99

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4