Algebra and Trigonometry: Structure and Method, Brown
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It takes a person the same time to drive 150 mi as it takes a plane to fly 1350 mi. If the plane is flying 400 mi/h faster than the car, how fast is each traveling?
Solution
50 mph and 450 mph.
It took a woman the same time to drive 150 mi as it takes a train to travel 250 mi. If the train is traveling 20 mi/h faster than the woman is driving, find the rate at which each is traveling.
Solution
30 mph and 50 mph.
Ralph can paint a 9-ft-by-12-ft room in 2 h, and Joy can paint the same room in 3 h. If they work together, how long would it take them to paint the room?
Solution
1 hour 12 minutes
A chemist has 6 L of a solution that is 8% salt. How much water should be evaporated so that the solution that remains is 40% water?
Solution
5.2 L
Mr. Clark invested a sum of money at 8%. He invested $1000 more at 9%. If his total income was $515, how much did he invest at each rate?
Solution
$2,500 at 8%, and $3,500 at 9%
Ms Stuart invested part of $4200 at 7% and the rest at 7.5%. If her total income from these investments was $306, how much did she invest at each rate?
Solution
$1,800 at 7% and $2,400 at 7.5%
How much of a 50% salt solution should be added to 80 L of a 5% salt solution to obtain a 30% salt solution?