Question: Marcos has to get across a 5 mile lake in his speedboat in 10 minutes so he can make it to work on time. How fast does he need to go in miles per hour to make it?
Answer with step-by-step thinking: 10 minutes for 5 miles means 10 minutes / 5 miles = 2 minutes / mile. 1 hour is 60 minutes so 60 minutes / hour / 2 minutes / mile = 30 miles / hour.
So the answer is 30.


Question: Janice adds 2 tablespoons of koolaid power and 16 tablespoons of water to a jug. She leaves it out long enough for 4 tablespoons of water to evaporate. Then she quadruples the amount of water in the jug. What percentage of the liquid in the jug is koolaid powder?
Answer with step-by-step thinking: First find how many tablespoons of water are left after the evaporation: 16 tbs - 4 tbs = 12 tbs. Then multiply this number by 4 to find how much water is in the jug after Janice refills it: 12 tbs * 4 = 48 tbs. Now add the 2 tablespoons of koolaid powder to find the total volume of the liquid in the jug: 48 tbs + 2 tbs = 50 tbs. Now divide the volume of the koolaid powder by the total volume and multiply by 100% to find the percentage of the liquid that's koolaid: 2 tbs / 50 tbs * 100% = 4%.
So the answer is 4.


Question: Together Felipe and Emilio needed a combined time of 7.5 years to build their homes. Felipe finished in half the time of Emilio. How many months did it take Felipe to build his house?
Answer with step-by-step thinking:
Let F = the number of years Felipe needed to build his house. Emilio = 2F. 3F = 7.5 years. F = 2.5 years. 2.5 years = 30 months. It took Felipe 30 months to build his house.
So the answer is 30.