SOLUTION: 1. If s is directly proportional to t, and s = 40 when t = 15, find t when s = 64. t = 0.025 t = 24 t = 170.67 t = 40 2. If a varies directly as b, and a = 75 when b = 40,

Question 428185: 1. If s is directly proportional to t, and s = 40 when t = 15, find t when s =
64.
t = 0.025 t = 24
t = 170.67 t = 40
2. If a varies directly as b, and a = 75 when b = 40, find a when b = 12.
a = 6.4 a = 0.4
a = 22.5 a = 2.25
3. If y is directly proportional to the square root of x, and y = 25 when x = 3,
find x when y = 100.
x = 3� 3 x = 48
x = 100 x = 12
4. If w varies directly as 2x - 1, and w = 9 when x = 2, find x when w = 15.
x = 2 x = 36
x = 5 x = 3
5. If a, b, and c are positive, and a divided by b is equal to b divided by c,
then b is called the mean proportion, or geometric mean, between a and c.�Find
the mean proportion between the pair of numbers:�3 and 27.
b = 9 b = 81
b = 27 b = 18
6. If a, b, and c are positive, and a divided by b is equal to b divided by c,
then b is called the mean proportion, or geometric mean, between a and c.�Find
the mean proportion between the pair of numbers:�5 and 15.
5� 3 b = 3
b = 75 3� 5
7. The acceleration of an object varies directly as the force acting on it.�If a
force of 240 newtons causes an acceleration of 150 m/s�, what force will cause
an acceleration of 100 m/s2?
160 newtons 16 newtons
62.5 newtons 62 newtons
8. At the grocery mart, a 575g can of green beans cost $0.39.�How much will an
810 g can of green beans cost?
$0.52 $0.50
$0.55 $0.53
9. A public opinion poll found that out of a sample of 450 voters, 252 favored a
school bond issue.�If 20,000 people voted, how many are likely to vote for the
bond measure?
15,714 11,200
1,120 10,100
10. The speed of an object falling from rest in a vacuum is directly
proportional to the time it has fallen.�After an object has fallen for 1.5
seconds, its speed is 14.7 m/s.�What is the speed after it has fallen 5 seconds?
20 m/s 51 m/s
49 m/s 50 m/s
11. Newton's law of cooling states that the rate at which an object cools varies
directly as the difference between its temperature and the temperature of the
surrounding air.�At the moment a steel plate at 270 degrees Celsius is placed in
air that is at 20 degrees Celsius, its rate of cooling is 50 degrees Celsius per
minute.�How fast is it cooling when the plate temperature is 100 degrees
Celsius?
24 degrees C/min 16 degrees C/min
14 degrees C/min 20 degrees C/min
Answer by richard1234(7193) (Show Source): You can put this solution on YOUR website!
One question per post, please.
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