Assume that the amount needed from the 5% solution is x and that the amount needed from the 65% solution is y.
We are given that, the final solution should be 42 ml, this means that:
x + y = 42 ...........> equation I
This can also be written as:
x = 42-y .......> equation II
We are also given that the final concentration should be 45%, this means that:
5% x + 65% y = 45% (x+y)
0.05x + 0.65y = 0.45(x+y)
We have x+y = 42 from equation I, therefore:
0.05x + 0.65y = 0.45(42)
0.05x + 0.65y = 18.9 .........> equation III
Substitute with equation II in equation III as follows:
0.05x + 0.65y = 18.9
0.05(42-y) + 0.65y = 18.9
2.1 - 0.05y + 0.65y = 18.9
0.6y = 18.9 - 2.1
0.6y = 16.8
y = 28 ml
Substitute with y in equation II to get x as follows:
x = 42-y
x = 42 - 28
x = 14 ml
Based on the above calculations:
amount of 5% solution = x = 14 ml
amount of 65% solution = y = 28 ml
The correct choice is:
The teacher will need 14 mL of the 5% solution and 28 mL of the 65% solution.
Alright! Given that C(x) is Cost(Students) = 558, we can eliminate:
2. 558 students paid to attend the event.
5. The event generated $124 from student revenue.
Now, in order to find the cost per student we simply divide 124 on both sides:

124 cancels on the left and 558/124 is 4.5 or $4.50.
Since we just determined the cost of one student, we can eliminate 3.
To check if 124 students paid, we simply add the cost to the equation and check:
4.5(124) = 558
558 = 558 √
It checks out, so we determined that both 1 and 4 are correct.
y=7x+12
Step-by-step explanation:
If you already have to start with 12 the c variable supply’s to 7 cause you don’t know how many people
Answer:
3 by 2
Step-by-step explanation:
3+2+3+2=10
3*2=6
Hope this Helps!!!
A2+B2=C2
12(2)+B(2)=27.1(2)
24+B=54.2
-24 -24
——————
B=30.2
Answer is 30.2
I hope this helps