Ratios & Unit Rates
Proportions
Scale Drawings
Percents, fractions, & decimals
Tax, Tips, Sales Price!
100
The average adult cat has 30 teeth. The average adult dog has 42 teeth. Write the ratio of cat's teeth to dog's teeth in three ways
30:42, 30/42, or 30 to 42 (15:21, 15/21, and 15 to 21 is simplest form)
100
Do the ratios form a proportion? 10/20, 30/40
no, no common multiple, cross products do not equal each other
100
write a scale for this unit ratio: a 10-inch-long drawing of a 40 inch-long table.
10/40 = 1/4 or 1 inch to 4 inches
100
Write 82% as a decimal
0.82
100
Find 7% of 50
0.07 X 50 = 3.5
200
Write 2 different ratios equal to 4/14.
2/7, 8/28 (and many others with a common multiple or divisor)
200
Three quarts of milk cost $2.97. How much will 7 quarts of milk cost?
$2.97 / 3 = x / 7; x = $6.93
200
map scale: Use a map scale of 1 cm : 100 km. How many centimeters on the map represent 170 kilometers.
1/100 = x / 170; 1.7 cm
200
write 3 % as a decimal
0.03, watch that decimal point!
200
You got your parents to take you out to eat! Estimate a 15% tip for your bill of $79.10.
about $12
300
Write 14:42 in simplest form.
1/3
300
Find the value of the variable: 42/g = 7/10
60
300
Write the scale as a ratio for a 4 ft tall model for a 128 ft tall statue.
4 : 128 = 1 ft to 32 feet
300
Write 14% as a fraction in simplest form.
14/100 = 7/50
300
You just bought a bicycle for $129. Using a sales tax rate of 7%, estimate the sales tax and total cost for your bike.
about $9.10 and $139.10
400
Who reads faster? Dylan reads 60 pages in 2 hours or Terry who reads 99 pages in 3 hours.
Dylan reads 30 pages / hour; Terry reads 33 pages / hour. Terry reads faster (better unit rate)
400
Solve x/9 = 4/6
use cross products: x = 6
400
Suppose you are making a model of a stop sign. Use a scale of 1 inch: 9 inches to find the height of your model. The stop sign is 117 inches tall.
1/9 = x/117; x = 13 inches
400
write 4/15 as a percent
4 divided by 15 = 27%
400
A hoodie is on sale for 20% off the regular price of $49.95. Estimate the sale price of the hoodie.
about $40
500
Comparison Shopping. Find each unit price. Determine the better buy: crackers: 16 oz for $2.39 or 20 oz for $3.19
$0.15 per oz; $0.16 per oz; 16 oz for $2.39 (just barely!)
500
A glacier moves about 12 inches every 36 hours. About how far does the glacier move in 90 hours.
12/36 =x/90; x = 30 in
500
Use a scale of 1 in = 8 ft to find the model length of a 14 ft automobile.
1/8 = x/14; 1.75 in
500
Write 28% as a fraction and as a decimal.
28 / 100 = 7/25; 0.28
500
A sleeping bag is on sale for $29.97. This is 25% off the original price. What is the regular price of the sleeping bag?
0.75 x s = 29.97; s = $39.96
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