Transcript document

Unit 8
Direct Proportion
Review
1. Which set of data below does
NOT show a constant rate of
change?
1. Answer
• D is not show a constant rate of change,
because the number of points scored
changes by adding 5. For a constant rate
of change, you need to multiply not add.
2. Which of the following graphs
shows a constant rate of change?
2. Answer
• D – this is the only graph that is in a
straight line.
1
3
2
3. A sugar recipe calls for
cups of
sugar to make 6 dozen cookies. Based
on the recipe, how many cups of sugar
must be used to make 20 dozen sugar
cookies?
1
A. 9
2
2
B. 11
3
C. 61 cups
D. 70 cups
3. Answer
B.
2
11
3
Solution:
1
3
x
2
6
20
4. The Madhany family traveled 3560
miles on a trip across the United
States. Since one mile is about 1.6
kilometers, which of the following is
closest to the total number of
kilometers in 3560 miles?
A. 5700 km
C. 3558 km
B. 4540 km
D. 2225 km
4. Answer
A. 5700 km
How to set up the
proportion
1 mi
3560 mi

1.6 km
x km
5. A city planner created the table below to show
the total number of seats for different numbers of
subway cars.
Which of the following represents the
relationship between x, the number of subway
cars, and y, the total number of seats, for the
data in the table?
A. y = 30x
C. y = 30 + x
B. x = 30y
D. x = 30 + y
5. Answer
A. y = 30x
y = kx
180 = k•6
30 = k
Solution
6. Old Faithful, the famous geyser in
Yellowstone National Park, erupts every
hour and sends 15,000 gallons of steam
and boiling water into the air. At the end of
one entire day, how many gallons of water
and steam would Old Faithful have sent
into the air?
A. 360,000
C. 153,000
B. 180,000
D. 36,000
6. Answer
A. 360,000 gallons
How to set up
the proportion.
15,000 gal
x

1 hr
24 hrs
7.
In the table below, x is proportional to y.
X
y
5
7
10
14
15
P
Q
28
What are the values of P & Q?
A. P = 20, Q = 21
C. P = 21, Q = 25
B. P = 17, Q = 21
D. P = 21, Q = 20
7. Answer
D. P = 21, Q = 20
Solution:
5 15

7 P
5 Q

7 28
8. There are 82 games in a
professional basketball season. If
a team has 25 wins and 16 losses,
and they win at the same rate for
the rest of the year, about how
many games will they win?
A. 41
B. 50
C. 54
D. 62
8. Answer
B. 50
How to set up the proportion:
25 wins
x

41 games 82 total games
9. Darnell caught 4 fish in 2 hours.
At that rate, how many fish will he
catch in 6 hours?
A. 4 fish
C. 10 fish
B. 8 fish
D. 12 fish
9. Answer
D. 12 fish
How to set up the proportion:
4 fish
x

2 hours 6 hours
10. The graph shows
the time it took
Hannah to walk a
certain distance.
What was Hannah’s
constant of variation
A. 100 ft per minute
C. 500 ft per minute
B. 200 ft per minute
D. 1000 ft per minute
10. Answer
B. 200 ft per minute
Solution:
y 1,000 ft

 200 ft/min
x
5 min
11. The graph
represents the
number of super
balls, y, produced
per second, x.
Using the graph,
determine the ratio
of super balls
produced per
second.
A. 1 super ball/sec
C. 3 super balls/sec
B. 2 super balls/sec
D. 4 super balls/sec
11. Answer
B. 2 super balls per second
12. In the table, y varies directly with
x. Which equation best describes the
data?
5
A. xy =
3
3
B. xy =
5
5
x
C. y =
3
3
x
D. y =
5
12. Answer
D. y =
3
x
5
Solution:
y
k
x
6
k
10
3
k
5
13. If m varies directly as p, and m = 5
when p = 7, what is the constant of
variation?
A. 35
B. 12
7
5
5
7
C.
D.
13. Answer
Solution:
m
p
5
7
Answer - D
14. The constant of proportionality
is the value of the ratio between y
and x; the coefficient (k) in the
equation of y = kx
A. True
B. False
14. Answer
A. True
15. Which is NOT a property of a
direct variation graph?
A. It is in the form of y = kx
B. It passes through the origin
C. As 1 variable increases, the other
variable decreases
D. The graph is a straight line
15. Answer
C.
In a direct variation – As one variable
increases the other variable increases