Some number y has 7 subtracted off to get 15. We have y-7 = 15. To isolate y, we have to undo the "subtract 7" operation that happens to y. We have to add 7 to both sides.
y-7 = 15
y-7+7 = 15+7
y = 22 is the answer
The original price would have been 60 dollars because 25%of 60 is 20 so take twenty from sixty and you get forty
After reading through the story problem, I ended up with this equation:
(35-2)(x+.5) =?
or
(35-2)(10+.5)=?
Explanation:
He sells 35 books for usual weeks. Since he is selling his books at $.50 more his average number of copies decreased by 2.
35-2 = 33
Next, we know that he adds $.50 for his price for each copy. If the price is $10 per copy than it looks like this:
$10+$.50= 10+.5
or if the price is not $10 it will be
$x+$.5= x+.5
6600 /minute so...
396,000 /hour