1. Proportion

2. Quantities will be in the same ratio!
Direct Proportion
Quantities will be in the same ratio!
When 2 quantities are in direct proportion, if one increases the other increases.
Also if one decreases, the other decreases.

3. 1) 1 bottle of water costs 40c. Find the cost of 2 bottles.
The Quantity and the Price are in DIRECT PROPORTION
2 bottles
? (more)
= 80 c or
40  2 = 80 c

4. 2) 4 chocolates cost 80c. Find the cost of 3 chocolates.
? (less)
60 c
How can you work it out?

5. 4 chocolates cost 80c. Find the cost of 3 chocolates.
80  4 =
20 c
3 chocolates
20  3 =
60 c

6. 3) We need 600 ml of water to make 3 glasses of orange squash
3) We need 600 ml of water to make 3 glasses of orange squash. How much water do we need to make 5 glasses ?
3 glasses
600 ml water
1 glass
600  3 =
200 ml
5 glasses
200  5 =
1000 ml
Ans: 1000 ml = 1l

7. Time to practice!
Find how much for ONE Then multiply by how many you need! This is called the unitary method!

8. 3 packets of batteries cost €6. What is the cost of 5 packets?
3 packets  €6 1 packet  €6 ÷ 3 = €2 5 packets  5 x €2 = €10

9. 5 bags of sweets contain 90 sweets
5 bags of sweets contain 90 sweets. Calculate how many sweets 7 bags will contain.
5 bags  90 sweets 1 bag  90 ÷ 5 = 18 7 bags 18 x 7 = 126 sweets

10. To make Tuna Stuffed Peppers for 8 people we need 200g tinned tuna
To make Tuna Stuffed Peppers for 8 people we need 200g tinned tuna. How much do we need for 5 people
8 people 200g 1 person  200 ÷ 8 = 25g 5 people  25 x 5 = 125g

11. The cost of 6 cakes is €4.20. Find the cost of 5 cakes.
6 cakes  € cake  €4.20 ÷ 6 = 70c 5 cakes 70c x 5 = €3.50

12. 3 packets of crisps weigh 84g. How much do 7 packets weigh?
3 packets  84g 1 packet  84g ÷ 3 = 28g 7 packets  28g x 7 = 196g

13. 4 monkeys eat 16 bananas in 1 minute
4 monkeys eat 16 bananas in 1 minute. How many bananas do 13 monkeys eat in 1 minute?
4 monkeys  16 bananas 1 monkey 16 ÷ 4 = 4 bananas 13 monkeys 4 x 13 = 52 bananas