Question 126701
The problem tells you that the price of premium is 5% more (or 0.05 times) than the price
of regular.
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Multiply the price of regular ($1.60) by 0.05 and you get $0.08 cents more. Then just add
the $0.08 to the price of regular and you get that the cost of premium is $1.68 per gallon. 
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Another way you can look at this problem is to say that the price of premium is 105% more
than the price of regular. 105% is the same as 1.05. So multiply the price of regular times
1.05 and you get that $1.60 times 1.05 = $1.68 per gallon. Same answer, just a little 
different way of viewing the problem.
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Just curious ... how old is your math text? And where in the US can you buy gasoline
nowadays for $1.60 per gallon?
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Hope this helps you to understand the problem a little better.
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