A box containing 15 DVDs is selling for $156.00. The box contains some DVDs worth $11.00 each and some DVDs worth $9.00 each. Which system of
equations can be used to determine x, the number of $11.00 DVDs, and y, the
number of $9.00 DVDs?

1 1/4 hours

step-by-step explanation:

2/4 + 2/4 + 1/4 = 5/4 or 1 1/4

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

the answer is

d.

5.3066 m2

step-by-step explanation: