X= # gallons of pure water that should be evaporated
The total amount of salt must be equal before and after evaporation.
STEP 1
BEFORE EVAPORATION: multiply the percent of salt in the solution before evaporation by the total gallons of solution
= 12% * 160 gallonsconvert 12% to decimal form (12% ÷ 100)
= 0.12 * 60
STEP 2
AFTER EVAPORATION: subtract the number of gallons of pure water that should be evaporated from the total number of gallons of the solution and multiply by the percent of salt in the solution after evaporation
= 20% * (160 - x)convert 20% to decimal form (20% ÷ 100)
= 0.20(160 - x)
STEP 3
Set the before & after evaporation equations equal to one another to solve for x.
0.12 * 160= 0.20(160 - x)multiply 0.20 by each term in parentheses
19.2= (0.20 * 160) + (0.20 * -x)multiply in parentheses
19.2 = 32 - 0.20xsubtract 32 from both sides
-12.8= -0.20xdivide both sides by -0.20
64 gallons= x
CHECK:substitute x= 64 into the step 3 equation
0.12 * 160= 0.20(160 - x)19.2= 0.20(160 - 64)subtract in parentheses19.2= 0.20(96)19.2= 19.2
ANSWER: 64 gallons of pure water should be evaporated.
Hope this helps! :)
Answer:
true
Step-by-step explanation:
Answer:
1) 11.9
2) 3.6
3) 18.9
4) 45.4
Step-by-step explanation:
Math
Answer:
37.2
Step-by-step explanation:
when you turn the small triangle LMN to its right angle to cover the right angle of KLM, you find that they are similar triangles.
therefore the corresponding side lengths are at the same ratio.
LM/KM = MN/LN
LM = 24
MN = 13
we can get LN via Pythagoras of the small triangle
LN² + MN² = LM²
LN² + 13² = 24²
LN² = 24² - 13² = 576 - 169 = 407
LN = sqrt(407) = 20.174241
now back to our main problem
24/KM = 13/sqrt(407)
24×sqrt(407)/13 = KM = 37.2
