Let x represent the number of liters of 50% acid Theresa puts into the mix. The the number of liters of 30% acid will be (420-x). The total amount of acid in the final solution will be ...
0.50x + 0.30(420-x) = 0.45(420)
0.20x + 126 = 189 . . . . . . . . . . . . . . . simplify
0.20x = 63 . . . . . . . . . . . . . . . . . . . . . subtract 126
x = 63/0.20 = 315 . . . . . . . . . . . . . . . liters of 50% solution
(420-x) = 420-315 = 105 . . . . . . . . . liters of 30% solution
Theresa should mix ...
105 liters of 30% solution
315 liters of 50% solution
24 bottles @ $3 = 8 bottles per dollar
12.5 cents per bottle
36 bottles @ $4 = 9 bottles per dollar
11.1 cents per bottle
Answer:
The son is five years old
Step-by-step explanation:
Let the son's age be x
A man is five as old as his son, 5x
In five years, he would be three times as old as his son
In five years: son would be x+5
Father 5x+5
3(x+5)=5x+5
3x+15=5x+5
Collect like terms
15-5=5x-3x
10=2x
Divide by 2
10/2=2x/2
x=5
The son is five years old
Answer: point estimate = 3.88
Margin of error = 0.63
Step-by-step explanation:
Confidence interval is written in the form,
(Point estimate - margin of error, Point estimate + margin of error)
The sample mean, x is the point estimate for the population mean. Let m represent the margin of error. Since the confidence interval is given as (3.25 , 4.51), it means that
x - m = 3.25
x + m = 4.51
Adding both equations, it becomes
2x = 7.76
x = 7.76/2
x = 3.88
Substituting x = 3.88 into x + m = 4.51, it becomes
3.88 + m = 4.51
m = 4.51 - 3.88
m = 0.63
