12. A wholesale warehouse buys pairs of sandals to sell. a. The warehouse can purchase 5 pairs of sandals for $65. What is the cost rate?

b. The warehouse can purchase 8 pairs of sandals for $96. What is the cost rate?

C. The warehouse can purchase 10 pairs of sandals for $126.50 and will get one
free pair. What is the cost rate?

d. Are any of the cost rates proportional? Explain.

e. Your buyer is to purchase 40 pairs of sandals. Use any combination of parts

(a), (b), and (c) for your buyer to purchase the 40 pairs of sandals at the
lowest possible cost.

You can just pick one you don’t have to do them all

This makes absolutely no sense at all young man/women

Ok here we go ..there are plenty of ways to solve such math problems but we will go for the smartest and easiest ..5x+2y=7  -2x+6y=9we rearrange them into the following ..by multiplying the 1st equation by 2 it becomes 10x + 4y = 14we rearrange it and so it becomes 10x = 14 - 4yas for the second equation we multiply it by 5 and rearrange it so it becomes as to the following ..-10x + 30y = 45rearranging so 10x = 30y -45now 10x equals both 14 - 4y and 30y -45so   14 - 4y = 30y -4531 = 26yy= 31/26 = 1.19 or around 1.2so by now we can calculate x easily as  -2x+6y=9so 2x = 6y -9 = 6 * 31/26 - 9 = -1.84  then x = - 0.92 or around -0.9best luck!