The price of a math textbook in the school bookshop is $45. If those sold in bookshops outside the school cost 20% less, how much can Peter save by buying from other bookshops rather than the school's if he wants to buy 3 math textbooks?
Let's think: 20% of $45 is (20 / 100) * $45 = $9. The price of the textbook in other bookshops cost $9 less than $45 which is $45 - $9 = $36. Three textbooks from the school bookshop would cost $45 * 3 = $135. Three textbooks from another bookshop would cost $36 * 3 = $108. Peter can save $135 - $108 = $27 by buying from another bookshop.. The answer is: 27.

There are 3 meatballs on each spaghetti plate. If Theresa's 3 sons each eat two-thirds of the meatballs on their respective plates, how many meatballs are still left on their plates altogether?
Let's think: Total meatballs on the plates 3 x 3 = 9. If two - thirds are eaten, one - third remaining on the plates is 9 / 3 = 3.. The answer is: 3.

Faith's neighborhood, with a total of 20 homes, decided to install solar panels. Each home needed 10 panels capable of providing their power needs. The supplier of the panels brought 50 panels less than the required amount. The neighbors agreed to only install the panels up to where they'd be finished. How many homes had their panels installed?
Let's think: The total number of panels required is 20 * 10 = 200 panels. When 50 failed to be delivered, the total number available for use became 200 - 50 = 150 panels. If each home requires 10 panels, the number of homes that had panels installed is 150 / 10 = 15 homes.. The answer is: 15.

Pete walks backwards three times faster than Susan walks forwards, and Tracy does one-handed cartwheels twice as fast as Susan walks forwards. But Pete can walk on his hands only one quarter the speed that Tracy can do cartwheels. If Pete walks on his hands at 2 miles per hour, how fast can Pete walk backwards, in miles per hour?
Let's think:
If Pete walks on hands at 1 / 4 what Tracy can do 1 - handed cartwheels, then Tracy can do 1 - handed cartwheels at 2 * 4 = 8 miles per hour. Since Tracy does 1 - handed cartwheels twice the rate of Susan's forward walking, then Susan walks at 8 / 2 = 4 miles per hour. Pete walks backwards 3x faster than Susan walks forward, and thus Pete walks backwards at 4 * 3 = 12 miles per hour.. The answer is: 12.