First change the mixed fraction into an improper fraction
7 1/2 = 15/2
Next, change multiply 2 to both numerator and denominator
15 x 2 = 30
2 x 2 = 4
30/4
Each piece needs 3/4 of an inch. Divide 30 with 3
30/3 = 10
c) 10 pieces is your answer
hope this helps
Lets call x the amount of 18% solution and y the amount of 40% solution, and write as equations the info of the problem:
18x + 40y = 10(20)
x + y = 10
lets multiply the second equation by -18 and add to the first:
18x + 40y = 200
-18x -<span> 18y = -180
</span>----------------------
0 + 22y = 20
y = 20/22 = 10/11
and substitute in the original equation:
x <span>+ y = 10
</span>x = 10 - y
x = 10 - 10/11
x = 110/11 - 10/11
x = 100/11
so they have to use 100/11 liters of 18% solution and 10/11 liters of 40% solution
The usual margin of error we strive for is a 95% probability that our estimate is within the margin. Assuming a normal distribution (and that we have a big enough sample not to worry about t tests) that corresponds to between minus and plus two standard deviations of the mean (remember the 68-95-99.7 rule). So our margin of error is plus or minus two standard deviations.
Answer: ±2%
Answer:
-70 is the correct answer
Step-by-step explanation:
To add fractions, find the LCD and then combine
