The answer would be right triangle. Hope that helps! :3
Oh and you spelled which wrong.
I think A, C, D are right because of the 12 pairs of heels, 6 are black (6/12) That means half of them could be chosen and be black (0.5). Another way to write 0.5 is as a percentage, 50%.
77.5d + .14m
m = 425
.14 * 425 = 59.5
77.5d + 59.5 ≤ 230
77.5d ≤ 170.5
d ≤ 170.5/77.5
d ≤ 2.2
if they only take payment for whole days, he has 2 whole days
I would make both denominators the same, and the lowest one that works is 18. So I'd make 1/9 into 2/18, and 1/6 into 3/18. They already used these times so combine them to make 5/18 then subtract that from the total time they had (18/18) and you would get 13/18 they spent playing music.