Answer:
51/12
as a mixed number
4 1/4
Step-by-step explanation:
first you add 8 to 4 which is 12
so the improper fraction would be 51/12
how to turn it in to a mixed number in simplest form
step 1 - Find Whole Number
Calculate out how many times the denominator goes into the numerator. To do that, divide 51 by 12 and keep only what is to the left of the decimal point:
51 / 12 = 4.2500 = 4
Step 2 - Find New Numerator
Multiply the answer from Step 1 by the denominator and deduct that from the original numerator.
51 - (12 x 4) = 3
Step 3 - Put Together
Keep the original denominator and use the answers from Step 1 and Step 2 to get this:
4
3
12
Step 4 - Minimize
Minimize the fraction part from Step 3 by dividing the numerator and denominator by 3, which is the greatest common factor, to get the final answer. 51/12 as a Mixed Number is:
4
1
4
Answer:
the amount of time until 23 pounds of salt remain in the tank is 0.088 minutes.
Step-by-step explanation:
The variation of the concentration of salt can be expressed as:

being
C1: the concentration of salt in the inflow
Qi: the flow entering the tank
C2: the concentration leaving the tank (the same concentration that is in every part of the tank at that moment)
Qo: the flow going out of the tank.
With no salt in the inflow (C1=0), the equation can be reduced to

Rearranging the equation, it becomes

Integrating both sides

It is known that the concentration at t=0 is 30 pounds in 60 gallons, so C(0) is 0.5 pounds/gallon.

The final equation for the concentration of salt at any given time is

To answer how long it will be until there are 23 pounds of salt in the tank, we can use the last equation:

Answer:
C. 70+20
Step-by-step explanation: