1. Simplify the following Ratios
18 : 36 : 72
350g : 7kg
0.12 : 2.4 : 6
1 : 2 : 4
Note that:
When the units are the same..they drop.
It is understood that when a ratio has no units then each part is of the same units!
1 : 20
1 : 20 : 50

2. Finding an unknown quantity in a given Ratio
A fruit drink is made by mixing lemon squash with water in the ratio 4:5. How much water needs to be added to 28cl of lemon squash to make the drink?
SQUASH : WATER 4 : 5
28 ÷ 4
x 7
x 7
28cl :
35cl ?
Therefore, 35cl of water needs to be added to make the drink.
(b)
To make Squirrel Grey paint, you need to mix Snow White and Beetle Black together in a ratio of 3:2. How much Snow White will you need if you’re using 18 litres of Beetle Black?
WHITE : BLACK 3 : 2
18 ÷ 2
x 9
x 9
27litres ? :
18litres
Therefore, 27litres of Snow White needs to be mixed to make Squirrel Grey. 2

3. Finding an unknown quantity in a given Ratio
The ratio of female to male members of a tennis club is 3 : 8. The total number of females in the club is 51. How many members are male?
FEMALE : MALE 3 : 8
51 ÷ 3
x 17
x 17 51 :
136 ?
Therefore, 136 members of the tennis club are male. 3

4. Ques 1
In a room, the ratio of men to women is 4:1. If there are 20 men, how many women are there?
TRUE – STAND UP FALSE – STAY PUT
5 women

5. Ques 2
In a shop the ratio of oranges to apples is 2:5. If there are 60 apples, how many oranges are there?
TRUE – STAND UP FALSE – STAY PUT
84 oranges

6. Ques 3
In a train the ratio of adults to children is 7:2. If there are 126 adults, how many children are there?
TRUE – STAND UP FALSE – STAY PUT
36 children

7. Ques 4
In a room, the ratio of men to women is 7:2. If there are 42 men, how many women are there?
TRUE – STAND UP FALSE – STAY PUT
12 women

8. Ques 5
In a box, the ratio of nails to screws is 8:4. If there are 16 screws, how many nails are there? TRUE – STAND UP FALSE – STAY PUT
10 nails
25.6

9. Ques 6
An alloy consists of copper, zinc and tin in the ratios 2:3:5. If there is 20g of copper, there are 30g of zinc and 50g of tin.
TRUE – STAND UP FALSE – STAY PUT
Alloy is type of metal made up of other metal

10. Ques 7 16 pages TRUE – STAND UP FALSE – STAY PUT
A ‘good’ children’s book is supposed to have pictures and text in the ratio 17 : 8. In a book I have just looked at, the pictures occupy 34 pages.
How many pages of text should this book have to be a ‘good’children’s book?
16 pages
TRUE – STAND UP FALSE – STAY PUT

11. Group of 4 : Numbered Heads
Olive is making cakes, she needs sugar and flour in the ratio 1:4. If she has 20g of sugar, how much flour does she need?
Tim is mixing red and white paint in the ratio 2:3. He has 10 litres of red, how much white does he need?
3. A Cocktail needs pineapple to apple in the ratio 3:7. How many bottles of apple juice should go with 9 bottles of pineapple juice?
4. Some peanuts, cashew nuts and walnuts are mixed in the ratio 1:3:5. How much of the other nuts are needed if 12 peanuts are used?

12. L.O. To be able to find an unknown quantity in a given ratio
It is the opposite of simplifying (so don’t simplify again – you must find the unknown quantity!)
Write the ratio in words in the correct order
Write the simplified ratio given under the words
Write the quantity that you know underneath the correct word & number
Find the quantity that you don’t know

13. L.O. To be able to find an unknown quantity in a given ratio