At one store, julia saved $10 with a coupon for 40% off her total purchase. at another store, the $29 she spent on books is 58% of her total bill. how much did julia spend in all at the two stores?

Let "a" and "b" represent the values of the first and second purchases, respectively.
  0.40*(original price of "a") = $10
  (original price of "a") = $10/0.40 = $25.00 . . . . divide by 0.40 and evaluate
  a = (original price of "a") - $10 . . . . . . Julia paid the price after the discount
  a = $25.00 -10.00 = $15.00

At the other store,
  $29 = 0.58b
  $29/0.58 = b = $50 . . . . . . . divide by the coefficient of b and evaluate

Then Julia's total spending is
  a + b = $15.00 +50.00 = $65.00

Julia spent $65 in all at the two stores.