Question: A store sells pencils and erasers. It has a rule that for every pencil you buy, you must buy 2 erasers which cost 1/2 the price of the pencils. If they sold 20 pencils and earned $80, how much do erasers cost?
Answer with step-by-step thinking: They sold 40 erasers because 20 x 2 = 40. Therefore 20(Pencil Price) + (1 / 2)(40 x Pencil Price) = 80. Therefore 40(Pencil Price) = 80. Therefore (Pencil Price) equals 2 because 80 / 40 = 2. An eraser costs $1 because 2 / 2 = 1.
So the answer is 1.

Question: Rick has just celebrated his 15th birthday. His oldest brother is twice his age, and his middle brother is a third of the oldest brother's age. The smallest brother is half the middle brother's age. If the youngest brother is 2 years younger than the smallest brother, how old, in years, is the youngest brother?
Answer with step-by-step thinking: Rick's oldest brother is 15 years * 2 = 30 years old. This means the middle brother is 30 years / 3 = 10 years old. The smallest brother is therefore 10 years / 2 = 5 years old. So the youngest brother is 5 years 2 years = 3 years old.
So the answer is 3.

Question: Bob wants to build a pyramid out of legos with 3 levels where the bottom level has 7 legos per side and each level has one less lego per side than the level below it. How many legos total will he need?
Answer with step-by-step thinking:
First find the total number of legos on the bottom layer: 7 legos * 7 legos = 49 legos. Then find the number of legos per side on the next layer: 7 legos - 1 lego = 6 legos. Then find the total number of legos on the second level: 6 legos * 6 legos = 36 legos. Then find the number of legos per side on the top level: 6 legos - 1 lego = 5 legos. Then find the total number of legos on the top level: 5 legos * 5 legos = 25 legos. Then add the number of legos on each level to find the total number of legos: 49 legos + 36 legos + 25 legos = 110 legos.
So the answer is 110.