#### Solved Examples and Worksheet for Application of Proportions involving Unit Prices

Q1The cost of 9 pizzas is $19. Find the cost of 27 pizzas. A.$57
B. $69 C.$114
D. $67 Step: 1 Let n be the cost of 27 pizzas. Step: 2 919 = 27n [Write a possible proportion.] Step: 3 9 × n = 19 × 27 [Write the cross products.] Step: 4 9 × n = 513 [Multiply.] Step: 5 9n9 = 5139 [Divide each side by 9.] Step: 6 n = 57 Step: 7 The cost of 27 pizzas is$57.
Correct Answer is :   $57 Q2At a fair 4 rides on a horse cost$10. Find the number of rides Andrew enjoyed, if he pays a total of $20. A. 9 B. 7 C. 8 D. 10 Step: 1 Let n be the number of horse rides Andrew enjoyed. Step: 2 410 = n20 [Write a proportion in terms of ridesamount.] Step: 3 4 × 20 = 10 × n [Write the cross products.] Step: 4 80 = 10n [Multiply.] Step: 5 8010 = 10n10 [Divide both sides by 10.] Step: 6 8 = n Step: 7 Number of rides Andrew enjoyed is 8. Correct Answer is : 8 Q3A museum charges$5.50 per person as an entry ticket. If a family paid $44 for the tickets, then find the number of people in the family. A. 15 B. 8 C. 10 D. 6 Step: 1 Let n be the total number of people in the family. Step: 2 numberentry fee, n44 = 15.50 [Write a possible proportion.] Step: 3 5.50 × n = 44 × 1 [Write the cross products.] Step: 4 5.50 n = 44 [Multiply.] Step: 5 5.50n5.50 = 445.50 [Divide both sides by 5.50.] Step: 6 n = 8 Step: 7 The total number of members in the family = 8. Correct Answer is : 8 Q4Brian bought 5 lb of candy for$25. Find the unit rate.
A. $7/lb B.$5/lb
C. $4/lb D.$6/lb

Step: 1
Rate = costweight
Step: 2
= $255lb [Substitute the values.] Step: 3 =$5/lb
[Simplify.]
Step: 4
The unit rate is $5/lb. Correct Answer is :$5/lb
Q5William bought 5 cups of milk for $4. Find the unit rate. A.$2.80/cup
B. $0.80/cup C.$4.80/cup
D. None of the above

Step: 1
Rate = $45cups =$0.80/cup
Step: 2
The unit rate is $0.80/cup. Correct Answer is :$0.80/cup
Q6Josh bought 3 pizzas for $2.50. How much would he pay for 6 pizzas? (Use proportions to find the amount.) A.$4
B. $6 C.$15
D. $5 Step: 1 Let$x be the required amount.
Step: 2
32.50 = 6x
[Write a proportion.]
Step: 3
3 × x = 6 × 2.5
[Cross multiply.]
Step: 4
3x = 15
[Multiply.]
Step: 5
x = 5
[Simplify.]
Step: 6
So, Josh has to pay $5 in order to buy 6 pizzas. Correct Answer is :$5
Q7Find the cost of 30 books, if 6 books cost $4. Assume each book costs the same. A.$20
B. $23 C.$24
D. $22 Step: 1 Let n be the cost of 30 books. Step: 2 46 = n30 [Write a possible proportion.] Step: 3 6 × n = 30 × 4 [Write the cross products.] Step: 4 6n = 120 [Multiply.] Step: 5 6n6 = 1206 [Divide both sides by 6.] Step: 6 n = 20 [Simplify.] Step: 7 The cost of 30 books is$20.
Correct Answer is :   $20 Q8Jim bought 4 dozen blackberries for$16. How many blackberries would Jim get for $24? A. 6 dozens B. 9 dozens C. 8 dozens D. 7 dozens Step: 1 Let n be the number of dozens Jim bought. Step: 2 416 = n24 [Write a proportion.] Step: 3 4 × 24 = 16 × n [Write the cross products.] Step: 4 96 = 16n [Multiply.] Step: 5 9616 = 16n16 [Divide both sides by 16.] Step: 6 6 = n Step: 7 Jim would get 6 dozens for$24.
Correct Answer is :   6 dozens
Q9The cost of 9 pastries is $19. Find the cost of 27 pastries. A.$57
B. $67 C.$114
D. $69 Step: 1 Let n be the cost of 27 pastries. Step: 2 919 = 27n [Write a possible proportion.] Step: 3 9 × n = 19 × 27 [Write the cross products.] Step: 4 9 × n = 513 [Multiply.] Step: 5 9n9 = 5139 [Divide each side by 9.] Step: 6 n = 57 Step: 7 The cost of 27 pastries is$57.
Correct Answer is :   $57 Q10The cost of 3 pens is$27. Which proportion could be solved to find x, the cost of 9 pens?

A. 327 = x9
B. 927 = 3x
C. 327 = 9x
D. 273 = 9x

Step: 1
Cost of 3 pens = $27 Step: 2 Let x be the cost of 9 pens. Step: 3 327 = 9x [Write the proportion.] Step: 4 So, cost of 9 pens can be found using the proportion 327 = 9x Correct Answer is : 327 = 9x Q11George earns$8 per hour. How many dollars will he earn, if he works for 6 hours?
A. $42 B.$48
C. $14 D.$40

Step: 1
16= 8n
[Write a possible proportion.]
Step: 2
n × 1 = 6 × 8
[Write the cross products.]
Step: 3
n = 48
Step: 4
George will earn $48, if he works for 6 hours. Correct Answer is :$48
Q12Select the best deal.
A. 5 fl oz bottle for $25 B. 3 fl oz bottle for$18
C. 2 fl oz bottle for $12 D. 10 fl oz bottle for$65

Step: 1
If the unit price of an item is the lowest compared to others, then that item is said to be the best deal.
Step: 2
Unit price of one fl ounce of bottle = costnumber
Step: 3
In case of '10 fl oz bottle for $65', the unit cost = 6510 =$6.5
[Express as a ratio and simplify.]
Step: 4
In case of ' 2 fl oz bottle for $12', the unit cost = 122 =$6
[Express as a ratio and simplify.]
Step: 5
In case of '5 fl oz bottle for $25', the unit cost = 255 =$5
[Express as a ratio and simplify.]
Step: 6
In case of ' 3 fl oz bottle for $18 ', the unit cost = 183 =$6
[Express as a ratio and simplify.]
Step: 7
Therefore, '5 fl oz bottle for $25' is the best deal. Correct Answer is : 5 fl oz bottle for$25
Q13Sarah wants to buy potatoes. Which is the best deal?

A. 1 kg for $5 B. 10 kg for$30
C. 5 kg for $20 D. 3 kg for$15

Step: 1
If the unit price of an item is the lowest compared to others, then that item is said to be the best deal.
Step: 2
Unit price of potatoes = Price of all the kgs of potatoesNumber of the kgs of potatoes
Step: 3
In case of 5kg for $20, the unit cost = 205 =$4
Step: 4
In case of 3kg for $15, the unit cost = 153 =$5
Step: 5
In case of 10kg for $30,the unit cost = 3010 =$3
Step: 6
In case of 1kg for $5, the unit cost = 51 =$5
Step: 7
Therefore, 10 kg for $30 is the best deal. Correct Answer is : 10 kg for$30
Q14Anna needs to buy some ribbons. The following deals are available at various stores. Choose the best deal.

A. $18 per 3 yd B.$25 per 6 yd
C. $7 per 1 yd D.$12 per 2 yd

Step: 1
If the unit price of an item is the lowest compared to others, then that item is said to be the best deal.
Step: 2
Unit price of the ribbons = Price of all the yards of the ribbonsNumber of yards
Step: 3
In case of '$7 per 1yd', the unit cost = 71 =$7
Step: 4
In case of '$12 per 2 yd', the unit cost = 122 =$6
Step: 5
In case of '$25 per 6yd', the unit cost = 256 =$4.16
Step: 6
In case of '$18 per 3yd', the unit cost = 183 =$6
Step: 7
Therefore, '$25per 6 yd' is the best deal. Correct Answer is :$25 per 6 yd
Q15Choose the best deal for apples.

A. $165.2 for 25 dozens B.$142.72 for 28 dozens
C. $33.95 for 7 dozens D.$30.56 for 5 dozens

Step: 1
If the unit price of an item is the lowest compared to others, then that item is said to be the best deal.
Step: 2
Unit price of apple = Price of all dozens of applesnumber of dozens
Step: 3
In case of '$165.2 for 25 dozens', the unit cost = 165.225 =$6.608
Step: 4
In case of '$33.95 for 7 dozens', the unit cost = 33.957 =$4.85
Step: 5
In case of '$30.56 for 5dozens', the unit cost = 30.565 =$6.112
Step: 6
In case of '$142.72 for 28 dozens', the unit cost = 142.7228 =$5.09
Step: 7
Therefore, '$33.95 for 7 dozens' is the best deal. Correct Answer is :$33.95 for 7 dozens