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: 2√ 10
Step-by-step explanation:
Answer:
Car A: 8 minutes
Car B: 6.67 minutes
Step-by-step explanation:
Car A: 60km evrery hour so,
1 km every minute, so he will be in 8km in 8 minutes.
Car B: 72km per hour so,
72/60 = 1.2 = 1.2 km per minute.
8/1.2 = 6.6666666666667 which is about 6.67 to the nearest hundredth.
Answer:
B.
Step-by-step explanation:
The direction of the arrow has to go the same way as the one in the question, from P to R. Also, the question only has one arrow, so the answer only has one arrow.
The area of a triangle is 1/2bh, which means The second choice is correct :)
Hope this helps!!
