The irrational number would be square root 15
4/5 (20x - 10)...use distributive property...basically multiplying the 4/5 by everything in the parenthesis,
4/5 * 20x - 4/5 * 10 =
16x - 8
There were 16 boys
-5:4, 10:8, 15:12, 20:16
-20:16 is 20+16=36
-20 were girls and 16 were boys
so a whole is same/same, in this context is 4/4 = 1, or four fourths.
now, we know 1/4 failed, that means 4/4 - 1/4 = 3/4 didn't fail, so 3/4 passed.
from that remaining 3/4, how many got an A? well 1/3, how much is 1/3 of 3/4? well is just their product,
.
so 1/4 of the remaining 3/4 got an A, that means 3/4 of the remaining 3/4 did NOT get an A.
how much is 3/4 of 3/4? well, is just their product.

Answer:35/24
Explanation:
7/9 divided by 8/15 can also be written as 7/9 x 15/8. We multiply the top and the bottom. It would look like 7x15/9x8. That equals 105/72. Simplified it is 35/24