I'm guessing the answer is B? I tried to isolate r and I got that result. Sorry if it's wrong!
So first I would say, what if all of them were dimes, how far away would it be from $14?
So 92 coins * 10 cents = $9.20
So it's 4.80 dollars away from 14 dollars.
So if we were to switch one to a quarter, it would increase by 0.15 cents.
So we want to see how many increases we need to reach 4.80 dollars more.
4.80/0.15 = 32
So there are 32 quarters and 60 dimes.
I cannot say I'm sure as I haven't learned this myself in class, however, I think it would also be 60. Apologies if I'm incorrect!!
You can set up proportions to find the width of the stream.
6/7.5=x/28
Cross multiply and solve for x.
168=7.5x
Divide by 7.5
x=22.4 ft
The stream is 22.4 ft wide