SOLUTION: Pleaseee i neeed help with this If we add 2 gallons of water to a 40 % alcohol solution, we get a 35% solution. How many gallons of the solution did we have initially? and

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Question 915062: Pleaseee i neeed help with this
If we add 2 gallons of water to a 40 % alcohol solution, we get a 35% solution.
How many gallons of the solution did we have initially?
and
Ashley ate 5 slices of pizza. Tiffany ate 2 (equal) slices. If Ashley ate 10/16
of the pizza, what fraction of the pizza was eaten?
Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
p is unknown quantity of 40 percent alcohol to start with.
40%2Ap%2F%28p%2B2%29=35
40p=35%28p%2B2%29
40p=35p%2B70
5p=70
p=70%2F5=%287%2A2%2A5%29%2F5
p=14 gallons


The pizza:
5 slices is 10%2F16 of the whole pizza.
1 slice is %281%2F5%29%2810%2F16%29=2%2F16=1%2F8 of the whole pizza.
Without further calculation on paper or on keyboard/screen, one-eighth of the pizza remains. ("mental" arithmetic may be sufficient, as long as analyzed well to find 1%2F8 pizza for 1 slice).
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How much was eaten? 7%2F8, 5 eighths plus 2 eighths.