Answer: choice A. 40 liters
====================================
Explanation:
x = number of liters of the 50% alcohol solution
If we have x liters of 50% alcohol, then we have 0.50*x liters of pure alcohol. This is added to 0.90*40 = 36 liters of pure alcohol (from the 90% solution).
So far we have 0.50*x + 36. This expression represents the total amount of pure alcohol. We want a 70% solution, so we want 70% of the total 40+x meaning 0.50*x + 36 is to be set equal to 0.70*(40+x) and we solve for x as shown below
0.50*x + 36 = 0.70*(40+x)
0.50*x + 36 = 0.70*(40)+0.70*(x)
0.50*x + 36 = 28+0.70*x
36 - 28 = 0.70*x - 0.50x
8 = 0.20x
0.20x = 8
x = 8/0.20
x = 40
So that is why the answer is choice A. 40 liters
Answer:
32 students are in the class.
Step-by-step explanation:
8 * 4 = 32
<em><u>Hope this helped! Have a nice day! Plz mark as brainliest!!! :D</u></em>
<em><u>-XxDeathshotxX</u></em>
Answer:
10
Step-by-step explanation:
10 dogs times 4 legs each
Answer:
Step-by-step explanation:
(168 mi)/(7 hr) = (24 mi)/hr
(2.5 hr) × (24 mi)/hr = 60 mi
Answer:
Step-by-step explanation:
(2x+5)(x+3)
2x^2+6x+5x+15
2x^2+11x+15
