Answer:
9.1 minutes.
Step-by-step explanation:
Let t represent time taken to fill the tank.
We have been given that a cold water faucet can fill a sink in 12 min, so the part of sink filed in 1 minute would be
.
The hot-water faucet can fill it in 15 min, so the part of sink filed in 1 minute would be
.
The drain can empty the sink in 25 min, so the part of drain emptied in 1 minute would be
.
The part of 1 full tank filled in t minutes, when both faucets are on and the drain is open would be:

Make a common denominator:









Therefore, it will take 9.1 minutes to fill the sink.
Answer:
Step-by-step explanation:
The given expression is

We will rewrite the expression

When we add the fraction
=
= 8
While Andre says the answer is 
because Andre added the denominator where he has to make a common denominator that should be 4 instead of 8.
Andre made mistake in this step
Picture is given below :
9514 1404 393
Answer:
$19.36
Step-by-step explanation:
Any average is the sum of numbers, divided by the number of them.
Here, the numbers are grouped, but the computation of the average works the same way.
The total value of donations received is ...
$100×10 +$50×20 +$20×30 +$10×100 +$5×35
= $1000 +1000 +600 +1000 +175 = $3775
The total number of donations received is ...
10 +20 +30 +100 +35 = 195
Then the average (mean) donation is the total value divided by the total number ...
$3775/195 ≈ $19.35897 ≈ $19.36 . . . mean donation