EXPONENTIAL GROWTH & DECAY
A population of rabbits starts at 50 and doubles every month. What is the population after 4 months?
What is 800 rabbits?
A train travels 240 miles in 4 hours. What is its average speed?
What is 60 mph?
How many pounds of nuts costing $8 per pound must be mixed with 5 pounds of nuts costing $5 per pound to make a mixture worth $6 per pound?
What is 2.5 pounds?
John can mow a lawn in 3 hours. His brother can mow the same lawn in 6 hours. How long will it take them working together?
What is 2 hours?
The sum of two numbers is 25. Their difference is 7. Find the numbers.
What are 16 and 9?
A car worth $25,000 depreciates 15% each year. What is its value after 3 years?
What is $15,331.25?
Two cars leave from the same point traveling in opposite directions. One travels at 55 mph, the other at 65 mph. How far apart are they after 2.5 hours?
What is 300 miles?
A chemist needs 100 ml of a 30% acid solution. She has 20% and 50% solutions available. How much of each should she use?
What is 66⅔ ml of 20% and 33⅓ ml of 50%?
Pipe A can fill a pool in 8 hours. Pipe B can fill it in 12 hours. How long to fill the pool with both pipes open?
What is 4.8 hours (or 4 hours 48 minutes)?
Adult tickets cost $8 and child tickets cost $5. If 120 tickets were sold for $810, how many of each type were sold?
What are 70 adult and 50 child tickets?
Bacteria in a petri dish triples every 2 hours. If there are 500 bacteria initially, how many will there be after 8 hours?
What is 40,500 bacteria?
A plane flies 450 miles with a tailwind of 30 mph in the same time it takes to fly 330 miles against the same wind. Find the plane's speed in still air.
What is 210 mph?
Coffee costing $12 per pound is mixed with coffee costing $9 per pound. If 20 pounds of the mixture costs $10.50 per pound, how many pounds of each type were used?
What is 10 pounds of each?
Machine A produces 150 widgets per hour. Machine B produces 100 widgets per hour. Working together, they need to produce 1,000 widgets. How long will it take?
What is 4 hours?
A rectangle has a perimeter of 54 cm. The length is 3 cm more than twice the width. Find the dimensions.
What is width = 8 cm and length = 19 cm?
A radioactive substance has a half-life of 6 years. If you start with 80 grams, how much remains after 18 years?
What is 10 grams?
Maria walks to school at 3 mph and rides her bike home at 12 mph. If the total trip takes 1 hour, how far is it to school?
What is 2.4 miles?
A pharmacist needs to prepare 500 ml of a 15% alcohol solution by mixing a 10% solution with a 25% solution. How much of each is needed?
What is 333⅓ ml of 10% and 166⅔ ml of 25%?
Sarah can complete a project in 15 days. Working with Tom, they can complete it in 6 days. How long would it take Tom alone?
What is 10 days?
Jake has $4.55 in quarters and dimes. He has 7 more dimes than quarters. How many of each coin does he have?
What are 11 quarters and 18 dimes?
An investment of $1,200 grows at 8% compounded annually. In how many years will it reach $2,000?
What is approximately 7 years?
A boat travels 36 miles downstream in 2 hours and returns upstream in 3 hours. Find the speed of the current.
What is 3 mph?
Antifreeze that is 40% alcohol is mixed with antifreeze that is 70% alcohol to create 12 gallons of antifreeze that is 55% alcohol. How many gallons of each type are needed?
What is 6 gallons of each?
Three printers working together can complete a job in 4 hours. Printer A alone takes 12 hours, Printer B alone takes 15 hours. How long does Printer C take alone?
What is 20 hours?
A boat travels 30 miles downstream in 2 hours and 18 miles upstream in 2 hours. Find the speed of the boat in still water and the speed of the current.
What is boat speed = 12 mph and current speed = 3 mph?