Mixtures
A chemist has 1 liter of a solution that is 90% acid. How much water must be added to make the resulting solution 45% acid?
1 liter
I left Boston and traveled 6.25 hours on an airplane to San Francisco. The distance between Boston and SF is 2985 miles. What was the average speed of the plane?
Avg. speed = 477.6 mph
The perimeter of an Isosceles triangles is 34 in. When you add the base of the triangle to one of the equal sides the sum is 18. What is the length of the base of the triangle?
2 in
Dave had 25 coins that consisted of nickels and quarters. If the value of the coins was $3.45, how many nickels did Dave have?
14 nickels
Luke can canoe at a speed of 3 mph on a still lake. Luke took a canoe trip down a river with a current that flowed at 2 mph. He then returned by paddling upstream to his starting point. What was his average speed for the trip?
1 2/3 mph
How much water much be added to a liter of alcohol to make the resulting mixture 80% alcohol?
1/4 liter
Erin took an 1800 mi trip. She avg. 55 mph for the frist 16 hrs and then slowed to 46 mph because of poor roads for the rest of the trip. What was her avg speed for the entire trip?
50 mph
The perimeter of a rectangle is 92 in. When you subtract the width from the length, the difference is 24 in. What is the width of the rectangle?
W = 11, L = 35
Connie had 6 more dimes than quarters. She also had 4 fewer nickels than quarters. If the value of her coins was $3.20, how many nickels does she have?
3 nickels
A jet flew against a head wind from Detroit to LA, a distance of 2000 mi, in 4.5 hours. The return trip at the same engine speed and same wind velocity (tail wind this time) took 4 hrs. What was the wind velocity?
27 7/9 mph
Coarse gravel sells for $40 a load. Fine gravel sells for $60 a load. How much of each kind of gravel should be used to make fifteen loads of a mixture selling for $44 a load?
12 coarse, 3 fine
Megan and kate decided to race their bikes. If Megan can ride at 12 mph and Kate can ride at 16 mph, how long until the are 1.5 miles apart?
22.5 min. (same direction), 5 min. (opposite directions)
The length of a rectangle is two meters more than its width. If its area is 255 sq m, what are its dimensions?
15m by 17m
Ben's allowance plus his friend's allowance equals $11.25. If Ben's allowance is tripled, their allowances would total $27.25. How much is Ben's allowance?
$8
Eddie's aunt is three times as old as he is. She is twice as old as his brother. Eddie is five years younger than his brother. What are the ages of the three people?
E = 10, A = 30, B = 15
Suppose enough skim milk is taken out to make the mixture 5% cream, 95% skim milk. How much skim milk is taken out?
No enough info.
Two planes leave from Chicago at noon. One heads directly east at 420 mph while the other heads west at 413 1/3 mph. At what time will they be 2000 miles apart?
2:24 PM
The area of a rectangle is 360 sq units. If one unit is added to both the length and the width of the rectangle, the new area is 400 sq units. What are the dimensions of the original rectangle?
15 units by 24 units
A barn was the home for ducks and cows. If there were 97 animals in the barn and there were 354 legs in the barn, how many cows are in the barn?
80 cows
If Joey were three times as old as he is, he would be twice as old as his sister is. His sister is five years older than Joey is now. How old is each?
J = 10, S = 15
20% of the selling price of item A is profit, and 25% of the selling price of item B is profit. How much of each kind of item must be sold in order to have an average profit of 22% on sales of $100?
$60 of A, $40 of B
It took Dana six minutes to circle a 1/4 mile track three times. What was her average speed in mph?
7.5 mph
A skier averaged 40 mph on the first third of a slope, 30 mph on the next third, and 20 mph the rest of the way. What was her overall average speed?
27 9/13 mph
Working together, a job takes Tom and Joe 8 days, Tom and Dave 13 1/3 days, and Joe and Dave 6 2/3 days. How long does it take each person to do the job alone?
20 days = Dave, 10 days = Joe, 40 days = Tom
Mr. Leonardo invested part of $6000 at 6% and the rest at 9%. How much was invested at each rate if the overall return was 8%?
$2000 at 6%, $4000 at 9%