Question: Otto’s local kitchen supply store charges $5.00 for the first knife that you need sharpened. They charge $4.00 for the next 3 knives and $3.00 for any knife after that. If Otto has 9 knives that need to be sharpened, how much will it cost to sharpen his knives?
Answer with step-by-step thinking: Knives 2, 3 & 4 will cost $4.00 each to sharpen so that’s 3 * 4 = $12.00. Knives 5 - 9 will cost $3.00 each to sharpen so that’s 5 * 3 = $15.00. The first knife will cost $5.00, the next 3 cost $12.00 and the rest cost $15.00 for a total of 5 + 12 + 15 = $32.00.
So the answer is 32.


Question: In twenty years, Ramon will be twice as old as Loui today. If Loui is currently 23 years old, how old is Ramon now?
Answer with step-by-step thinking: If Loui is currently 23 years old, twice her age, which is the same as twice Ramon's age in twenty years, is 23 * 2 = 46. If in twenty years Ramon will be 46, currently he is 46 - 20 = 26 years old.
So the answer is 26.


Question: An iron bar measures 12 cm by 8 cm by 6 cm. A factory wants to melt ten iron bars and mold them into iron balls. Each iron ball has a volume of 8 cubic cm. How many iron balls have been molded?
Answer with step-by-step thinking:
The volume of 1 iron bar is 12 cm x 8 cm x 6 cm = 576 cubic cm. The volume of 10 iron bars is 10 x 576 cubic cm = 5760 cubic cm. Therefore, there are 5760 / 8 = 720 iron balls that have been molded.
So the answer is 720.