Ratio

Question 1

Share £50 in the ratio 3:2

I suggest using a piece of paper and writing this down, but you’re lazy so you’ll just do it in your head anyway

Answer 1

3 + 2 = 5
£50 / 5 = 10
Each person is worth £10
£30:£20

Question 2

What are ratios used to do?

Answer 2

Compare amounts

Question 3

When is something in direct proportion?

Answer 3

If quantities increase at the same rate then we say they are in Direct Proportion to each other

Question 4

If 9 pens cost 63p, how much do 3 pens cost?(ratio, direct proportion)

Answer 4

9 pens : 63p
Divided by 3
1 pen = 63/9 = 7p
Times 3
3 pens : 21p

Question 5

When is something in inverse proportion?

Answer 5

If one quantity increases at the same rate as another decreases we say they are in inverse proportion to each other

Question 6

1 man takes 6 days to paint a house. How long would it take 3 men to paint the house? (Ratio, inverse proportion)

Answer 6

1:6
Times 3 | divided by 3
3:2

Question 7

In ratio what do the units have to be?

Answer 7

The same

Question 8

In simple interest, if I have £10 one year and it increases due to simple interest, why is my interest calculated from in the next year?

Answer 8

The original £10

Question 9

In compound interest, if I have £10 one year and it increases due to simple interest, why is my interest calculated from in the next year?

Answer 9

Total money in account (£10+gained)

Question 10

1 mile = ?meters = ?km

Answer 10

1 mile = 1600meters = 1.6km

Question 11

1km = ? Miles

Answer 11

1km = 0.62 miles

Question 12

1 mm = ?cm = ?meters

Answer 12

1mm = 0.1cm = 0.001meters

Question 13

1000mm^3 = ?cm^3 = ?m^3

Answer 13

1000mm^3 = 1cm^3 = 0.000001meters^3

Question 14

1mm^3 = ? = ?meters ^3

Answer 14

1mm^3 = 0.001cm = 0.000000001m^3

Question 15

1 gallon = ?litres

Answer 15

1 gallon = 4.55litres

Question 16

1litre = ? Gallon = 1,000ml

Answer 16

1 litre = 0.22Gallons = 1,000ml

Question 17

1 kg = ?lbs

Answer 17

1 kg = 2.2lbs

Question 18

1lbs = ?kg

Answer 18

1lbs = 0.45kg

Question 19

What does a direct proportion graph look like?

Answer 19

Top left to top right positive gradient

Question 20

What are the five steps to work out the formula connecting y and x when:

Y is directly proportional to x
X = 30 Y = 45

Answer 20

Y {proportional} x
45 {proportional} 30
45 = k x 30
45/30 = k
K = 1.5

Question 21

Y is directly proportional to x

K = 1.5
Find y when X = 40

Answer 21

K = 1.5 X
Y = 1.5 x 40
Y = 60

Question 22

In direct proportion, what does ‘K’ represent?

Answer 22

The Constant