Answer:
13.765
17.09
Step-by-step explanation:
Answer:
its a fraction but you use proportions to find x
for example :
2 ×
- -
3 2
Step-by-step explanation:
you multiply cross so then you divide that by your other number
Answer:
14,464
Step-by-step explanation:
16,000 - 20% = 12,800
12,800 + 13% = 14,464
I hoope this is correct. Have a wonderful day and dream a good dream of good people. :)
This is a classic example of where you would need to use the process of elimination. Let's start with answer A, 3 classes.
If A were to be correct, 3 classes of 45 minutes each would be 132 greater than the amount he paid, 3 classes worth $12. We could easily express this as a math equation:
45 * 3 = 132 + (12 * 3) Then, all you would have to do is simplify:
135 = 132 + 36
135 = 168
Obviously this equation isn't true, and you can continue with answer choice B.
But wait... there's a better way. Using this starting equation, we can come up with a formula to solve for c, the number of classes. Let's take our starting equation:
45 * 3 = 132 + (12 * 3) Now, let's turn all the 3s into cs.
45c = 132 + 12c Then, using algebra, we can solve this equation.
-12c - 12c
33c = 132
33c/33 = 132/33
c = 4
And finally, we have our answer, B! I hope both methods help you in your further studies.
Let 
be the number of liters of the 10% solution to be used, and 
the number of liters of the 4% solution. The chemist wants to end up with a 4 liter solution, so
For each liter used in the mixture, a concentration of either 10% or 4% acid will be contributed, and the goal is to make a 4L solution whose concentration is 7%, which means
Solving for 
gives 
, so 2L of both solutions is needed.
