Answer:
-1+2x= 17
2x=18
x=9
Step-by-step explanation:
ans. 9
Answer:
Step-by-step explanation:
26% is (26-20)/(50-20) = 6/30 = 1/5 of the way between 20% and 50%. That means 1/5 of the solution is 50% acid.
50% acid: 1/5 · 100 mL = 20 mL
20% acid: 100 mL -20 mL = 80 mL
Delbert must mix 80 mL of 20% acid and 20 mL of 50% acid.
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Maybe you'd like to see an equation. Let x represent the amount of 50% acid required. Then 100-x is the amount of 20% acid needed. The amount of acid in the mix is ...
0.50(x) +0.20(100 -x) = 0.26(100)
(0.50 -0.20)x = (0.26 -0.20)100 . . . . subtract 0.20(100)
x = (0.26 -0.20)/(0.50 -0.20)×100 = 20
This last expression should look a lot like the one we started with in this answer. It shows you how you can almost write down the answer to mixture problems without a lot of work.
the fraction that is equivalent to 4/6 is 2/3
We can drop the absolute value and the signs, and the integer part if they're all the same, and then make a common denominator and check for a decreasing sequence.
10/12, 7/12, 5/12 -- Check decreasing
3 1/3, 3 2/3, 2 2/3 -- nope, increases then decreases
6 5/7, 6 3/7, 5 2/7 - Check, decreasing
11 7/10, 11 6/10, 10 3/10 -- Check, decreasing
Answer: A,C,D
