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.
Answer:
i believe its C
Step-by-step explanation:
<em>The formula for area of a triangle is bh × 1/2.</em>
(b) Base: 7
(h) Height: 24
24 × 7 × 0.5 = 84
The area of the triangle is 84 units²
800 + 60 + 3 + 0.1 + 0.04 + 0.002
Solve the system of equations by the addition method.
6x - y = 12
6x + y = 0
——————
12x = 12
12x/12 = 12/12
X = 1
Now plug x back into one of the equations.
6x + y = 0
6(1) + y = 0
6 + y = 0
(Subtract both sides by 6)
Y = -6