The cost of the planks for one birdhouse is 7 * 3 = $21. And the nails are a cost of 20 * 0.05 = $1 for each birdhouse. So to build one birdhouse one will need 21 + 1 = $22. So the cost of building 4 birdhouses is at 4 * 22 = $88.
The answer: 88
Reverse engineering the question: Building one birdhouse requires 7 planks and 20 nails. If 1 nail costs $0.05, and one plank costs $3, what is the cost, in dollars, to build 4 birdhouses?
Reasoning and answer: Mondays: 7 * 1.5 = 10.5. Tuesdays: 9 * 2.5 = 22.5. 22.5 - 10.5 = 12 cm. It rained 12 centimeters more on Tuesdays than on Mondays.
The answer: 12
What was the question?
Question: On each of 7 Mondays, it rained 1.5 centimeters. On each of 9 Tuesdays it rained 2.5 centimeters. How many more centimeters did it rain on Tuesdays than Mondays?
First figure out how old Ana is right now by subtracting 3 from 15: 15 - 3 = 12. Next, figure out how old Billy is by dividing Ana's age by 2: 12 / 2 = 6. Now figure out how old Mark is by adding 4 to Billy's age: 6 + 4 = 10. Now, to figure out Sarah's age, first multiply Mark's age by 3: 10 * 3 = 30. Finally, subtract 4 from triple Mark's age to find Sarah's age: 30 - 4 = 26.
The answer: 26
Reverse engineering the question: Sarah's age is equal to three times Mark's age minus 4. Mark is four years older than Billy. Billy is half Ana's age. If Ana will be 15 in 3 years, how old is Sarah?
Reasoning and answer: If seven more rabbits are added to the thirteen in the cage, the total number becomes 7 + 13 = 20. Triple the number of rabbits in the cage is 3 * 20 = 60, the same as the number of rabbits that Jasper saw at the park today.
The answer: 60
What was the question?
Question: If seven more rabbits are added to the thirteen in the cage, the number of rabbits in the cage will be 1/3 the number of rabbits Jasper saw in the park today. How many rabbits did Jasper see in the park today?
The train ride takes Andrew 2 * 10 = 20 hours. Together, the subway ride and the train ride take Andrew 10 + 20 = 30 hours. With an additional bike ride of 8 hours to reach the Bronx, Andrew takes 30 + 8 = 38 hours to travel from Manhattan to the Bronx.
The answer: 38
Reverse engineering the question: Traveling from Manhattan to the Bronx, Andrew rides the subway for 10 hours, takes the train and rides for twice as much time as the subway ride, and then bikes the remaining distance for 8 hours. What's the total time he takes to reach the Bronx from Manhattan?
First find the total number of people by adding the number of passengers and flight crew: 30 people + 5 people = 35 people. Then find the total number of bags by doubling the total number of people: 35 people * 2 bags / person = 70 bags. Then find the fuel increase caused by the people by multiplying their number by the fuel increase per person: 35 people * 3 gallons / mile / person = 105 gallons / mile. Then multiply the number of bags by the fuel increase per bag to find the total fuel increase they cause: 70 bags * 2 gallons / mile / bag = 140 gallons / mile. Now add the fuel increases to the base fuel consumption to find the total fuel needed per mile: 140 gallons / mile + 105 gallons / mile + 20 gallons / mile = 265 gallons / mile. Now multiply the fuel consumption per mile by the number of miles flown to find the total amount of fuel needed: 265 gallons / mile * 400 miles = 106,000 gallons of fuel.
The answer: 106000
Reverse engineering the question:
Carol is an aviation engineer deciding how much fuel to put in a jet. The empty plane needs 20 gallons of fuel per mile. Each person on the plane increases this amount by 3 gallons per mile, and each bag increases it by 2 gallons per mile. If there are 30 passengers and 5 flight crew, and each person brought two bags, how many gallons of fuel does the plane need for a 400-mile trip?