MATHEMATICS
Direct Proportion
Direct Proportion is an equation stating two ratios are equal.
Notice that all the ratios below are equal. Therefore, each equation is a proportion.
4 12

9 27
5 10

7 14
45km 90km

1L
2L
Example: A truck will travel 100 km on 8 L of gasoline. How far will it travel on 40 L of gasoline?
100km  km

8L
40 L
 km 
100km  40 L   km  40 L 

8L
40 L
100km  40 L 
  km
8L
100km  40 L  100km  5 

 500km
8L
1
Solve the following questions:
1. Tim Horton’s sells three doughnuts for $1.80. Assuming no discount, how much will 24 doughnuts
cost?
2. The ratio of chicken to beef in a certain dog food is 2:5. If 180 kg of chicken is used in a batch of dog
2
food, how many kg of beef are needed? (2:5 = )
5
3. If a piece of stock tapers 1 in. in 28 inches, what is the amount of taper of a 36 in. piece of stock?
4. A 7 ft. post casts a 6 ft. shadow on the ground. How tall is a nearby tree that casts a 30-ft. shadow?
dearthdancer@rrc.ca
Academic Success Centre
www.rrc.mb.ca/lac
http://www.youtube.com/rrcwiseguys
http://blogs.rrc.ca/delaney/
Page | 1
MATHEMATICS
5. A wire 390 m long has a resistance of 2.35 ohms (Ω). How long is a wire of the same diameter if the
resistance is 5.24 Ω. (Round answer to the nearest whole number.)
6. Two angles have a ratio of 6 to 1. How many degrees are in the larger angle if there are 15° in the
smaller angle?
7. An alloy of tin and silver has a mass of 75 kg. If there are 14 parts of tin for each part of silver, how
much silver is in the alloy?
8. In preparing for a banquet for 40 people, a cater uses 24 kg of potatoes. How many kg of potatoes will
be needed for a banquet of 185 people?
9. In a pond at Oak Hammock marsh, there are 36 waterfowl. Of that total, 21 are ducks and the rest are
Canada geese. If this is typical of all the waterfowl in all the ponds in the marsh, how many geese are
there at Oak Hammock marsh if there are 96 300 waterfowl in the entire marsh?
10. The ratio of men to women in technical and trade occupations is estimated to be 5 to 2, that is
5
.
2
What is the total number of people employed in such occupations if 56 250 of them are men?
11. Suppose 2.5 cm on a map represents 300 km on the ground. How many kilometres on the ground will
be represented by 7.5 cm on the map?
12. An investment of $4000 yields a return of $$250 in a year. If you wanted a return of $2000, how much
should you have invested?
Answers:
1. $14.40
2. 450 kg
3. 1.3 in.
dearthdancer@rrc.ca
4. 35 ft
5. 870 m.
6. 90°
7. 5 kg
8. 111 kg
9. 40 125 geese
10. 78 750 people
11. 900 km
12. $32 000.00
Academic Success Centre
www.rrc.mb.ca/lac
http://www.youtube.com/rrcwiseguys
http://blogs.rrc.ca/delaney/
Page | 2