Bell Ringer: 10-20-14images.pcmac.org/SiSFiles/Schools/TX/Alvarado... · 2019. 9. 26. · Weeks 2 4...
Transcript of Bell Ringer: 10-20-14images.pcmac.org/SiSFiles/Schools/TX/Alvarado... · 2019. 9. 26. · Weeks 2 4...
Write each decimal as a percent.
1) 0.46
2) 2.47
3) 0.03
4) 5.236
1) 46%
2) 247%
3) 3%
4) 523.6%
Bell Ringer: 10-20-14
1. A machine makes 450 boxes in 20 minutes. Which
expression equals the unit rate in boxes per hour?
A. 450 20
B. 450 1
3
C. 450 20
D. 450 1
3
2. Which rectangle is similar to a rectangle 5 inches wide
and 8 inches long?
A. 18 inches wide and 27 inches long
B. 20 inches wide and 32 inches long
C. 24 inches wide and 32 inches long
D. 30 inches wide and 40 inches long
3. The rectangles are similar. Side AB = 5 and AD = 7.
In the big rectangle, side ML = 4.5. Find side KL.
A. 5.2
B. 6.3
C. 9.5
D. 6.5
4. A map scale is 3 in. : 45 mi. Two cities are 675 miles
apart. How far apart are the cities on the map?
A. 36 inches
B. 2025 inches
C. 45 inches
D. 54 inches
5. The table shows a person saving money at a
constant rate. How much will this person save in 49
days?
A. $210
B. $343
C. $150
D. $120
Weeks 2 4 6 8
Total Savings ($) 60 120 180 240
Time (Minutes) Distance (Miles)
0 0
12 11
15 13.75
30 27.5
45 41.25
6. The table below shows the time it takes a prototype
car to travel different distances. What is the constant
rate of change in this situation in miles per 2 hours?
A. 110 miles per hour
B. 68.75 miles per hour
C. 27.5 miles per hour
D. 55 miles per hour
7. Tim’s mom filled the gas tank in her SUV and spent
$68.00 for 20.5 gallons of unleaded gasoline. What is
the constant of proportionality in this situation?
F. $2.31 per gallon of unleaded gas
G. $3.32 per gallon of unleaded gas
H. $3.16 per gallon of unleaded gas
J. $0.32 per gallon of unleaded gas
8. Ken was pricing ingredients for a recipe he was planning to
make for a dinner party. The store sold 4 different brands of the
same type of product.
Which statement is true about the unit costs of the different
brands?
F. Brand C has a lower unit cost than Brand B.
G. Brand D has a higher unit cost than Brand A.
H. Brand A and Brand C have the same unit cost.
J. Not here
Brand A Brand B Brand C Brand D
8 oz
$2.88
4.5 oz
$1.44
5 oz
$1.50
4 oz
$1.20
9. John’s lost 1.24 kilograms after a week of exercise. If
1 kilogram is approximately 2.5 pounds, about how
many pounds did John lose?
A. 3.74 lb.
B. 3.10 lb.
C. 3.12 lb.
D. 3.64 lb.
10. Susan rides her bicycle 6 miles in 1
4 of an hour. At
this rate, how many miles could she ride in 2 hours?
A. 24 mi.
B. 18 mi.
C. 55 mi
D. 48 mi.
11. Carrie missed 14.3% of the problems on a test. The
test had a total of 105 problems. Which of the following
is the best estimate of the number of problems Carrie
got correct?
A. 95 problems
B. 100 problems
C. 105 problems
D. 90 problems
12. Of the 420 sheep in a flock, 22% are white. What is
the total number of white sheep in the flock?
A. 86 sheep
B. 74 sheep
C. 93 sheep
D. 81 sheep
13. Marty can walk 21
7 miles in 34 minutes. How many
minutes does it take Marty to walk 1 mile?
A. 1611
14
B. 147
8
C. 1513
15
D. 142
7
You go to the store to purchase a bag of dog food that normally costs $16.50. Today it is on sale for 20% off. You also have to pay 8.5% sales tax. How much money do you need in order to buy the dog food?
If you then split the dog food with your friend, how much do each of you have to pay?
Bell Ringer: 10-22-14
Finding Percent Increase
The percent an amount increases or decreases from its original
amount is the percent of change.
Percent increase describes how much a quantity increases in
comparison to the original amount.
Percent of Change =
Percent of Change =
My Favorite Way: (Proportions)
Percent of Change =
Then subtract the original percent from the new percent to find the percent increase.
Amount of Change
Original Amount
New – Old
Old
𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 #
100% =
𝑁𝑒𝑤 #
𝑁𝑒𝑤 𝑃𝑒𝑟𝑐𝑒𝑛𝑡
Find the percent increase from 10 to 12
1st: Find amount of increase:
12 – 10 = 2
2nd: set up fraction.
Percent of increase = amount of change
original amount
0.2 =
Divide to find
the decimal.
Move decimal
2 places to the
right
Percent
increase from
10 to 12 is
20%
20% 12 −10
10 =
2
10 =
Step 1: 10
100% =
12
____%
Step 2: 120% - 100%
20%
Find the percent increase from 5 to 7
1st: Find amount of increase:
7 – 5 = 2
2nd: set up fraction.
Percent of increase = amount of change
original amount
0.4 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
increase from
5 to 7 is 40%
40% 7 −5
5 =
2
5 =
Step 1: 5
100% =
7
____%
Step 2: 140% - 100%
40%
Find the percent increase from 2 to 12
1st: Find amount of increase:
12 – 2 = 10
2nd: set up fraction.
Percent of increase = amount of change
original amount
5 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
increase from
2 to 12 is
500%
500% 12 −2
2 =
10
2 =
Step 1: 2
100% =
12
____%
Step 2: 600% - 100%
500%
Find the percent increase from 4 to 7.5
1st: Find amount of increase:
7.5 – 4 = 3.5
2nd: set up fraction.
Percent of increase = amount of change
original amount
0.875 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
increase from
4 to 7.5 is
87.5%
87.5% 7.5 −4
4 =
3.5
4 =
Step 1: 4
100% =
7.5
____%
Step 2: 187.5% - 100%
87.5%
Now You Try: Find each percent increase.
From 100 to 114
From 2.0 to 3.2
From 4,000 to 8,500
14%
60%
112.5%
114 −100
100 =
3.2 −2
2 =
8,500 −4,000
4,000 =
14
100 =
1.2
2 =
4,500
4,000 =
.14 =
.6 =
1.125 =
Step 1: 100
100% =
114
____%
Step 2: 114% - 100%
14%
Step 1: 2
100% =
3.2
____%
Step 2: 160% - 100%
60%
Step 1: 4000
100% =
8500
____%
Step 2: 212.5% - 100% 112.5%
Find each percent increase.
• From 50 to 75
• From 2.0 to 3.5
• From 8,000 to 16,400
50%
75%
105%
Bell Ringer: 10-23-14
The annual production of video games in
the United States has more than doubled
since the 1960s. Find the percent increase
from 1960 to 1990.
Year Number of Video
Games Produced
1960 88,000
1990 205,000
Percent of increase from 1960-1990 was about 133%.
205,000 −88,000
88,000 =
117,000
88,000 = 1.329 = 132.9%
Step 1: 88000
100% =
205000
____%
Step 2: 232.95% - 100%
132.95%
Finding Percent Decrease Percent Decrease describes how much a quantity decreases in
comparison to the original amount.
Percent Decrease is found the SAME way that Percent of Increase is.
1st: Find amount of decrease:
(Greater # – Smaller #) = Amount of Change
2nd: Set up your fraction:
3rd: Divide and move decimal 2 places to the right.
My Favorite Way: (Proportions)
Percent of Change =
Now subtract the new percent from the original percent in order to get your answer.
amount of change
original amount
𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 #
100% =
𝑁𝑒𝑤 #
𝑁𝑒𝑤 𝑃𝑒𝑟𝑐𝑒𝑛𝑡
Find the percent decrease from 12 to 9
1st: Find amount of decrease:
12 – 9 = 3
2nd: set up fraction.
Percent of decrease = amount of change
original amount
0.25 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
decrease from
12 to 9 is 25%
25% 12 −9
12 =
3
12 =
Step 1: 12
100% =
9
____%
Step 2: 100% - 75%
25%
Find the percent decrease from 10 to 8
1st: Find amount of decrease:
10 – 8 = 2
2nd: set up fraction.
Percent of decrease = amount of change
original amount
0.2 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
decrease from
10 to 8 is 20%
20% 10 −8
10 =
2
10 =
Step 1: 10
100% =
8
____%
Step 2: 100% - 80%
20%
Find the percent decrease from 125 to 115
1st: Find amount of decrease:
125 – 115 = 10
2nd: set up fraction.
Percent of decrease = amount of change
original amount
0.08 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
decrease from
125 to 115 is
8%
8% 125 −115
125 =
10
125 =
Step 1: 125
100% =
115
____%
Step 2: 100% - 92%
8%
Find the percent decrease from 65 to 35.75
1st: Find amount of decrease:
65 – 35.75 = 29.25
2nd: set up fraction.
Percent of decrease = amount of change
original amount
0.45 =
Divide to find
the decimal.
Move decimal 2
places to the
right
Percent
decrease from
65 to 35.75 is
45%
45% 65 −35.75
65 =
29.25
65 =
Step 1: 65
100% =
35.75
____%
Step 2: 100% - 55%
45%
Now Your Turn: Find the percent decrease to the nearest
whole percent.
From 9.6 to 4.8
From 202 to 192
From 854.5 to 60.6
50%
5%
93%
9.6 −4.8
9.6 =
4.8
9.6 = 0.5 =
202 −192
202 =
10
202 = 0.0495 =
854.5 −60.6
854.5 =
793.9
854.5 = 0.9290 =
Step 1: 9.6
100% =
4.8
____%
Step 2: 100% - 50%
50%
Step 1: 202
100% =
192
____%
Step 2: 100% - 95%
5%
Step 1: 854.5
100% =
60.6
____%
Step 2: 100% - 7%
93%
A computer that costs $875 last year costs $745 this
year. Find the percent decrease to the nearest whole
percent.
14.85% = 875 −745
875 =
130
875 = 0.1485 = 15%
Step 1: 875
100% =
745
____%
Step 2: 100% - 85%
15%
Bell Ringer: 10-24-14
Using Percent of Change • Given an original amount and a percent increase or
decrease, you can use the percent of change to find the new
amount.
Ex. The grizzly bear population in Yellowstone National Park
in 1970 was about 270. Over the next 35 years, it increased by
about 115%. What was the population in 2005?
Step 1: 270 𝐵
100% =
? 𝐵
215%
Step 2: 270 x 2.15
580.5 Bears = 581 Bears