Ratios
What is 3/8 of 16?
6
Name a real-life example of where you might find a scale.
map
blueprints
A recipe for 10 people requires 20 apples. How many apples are needed for a recipe for 5 people?
10 apples
What is the base equation for direct proportion?
y=mx
What is the base equation for indirect proportion?
y= m/x
Share CHF 60 in the ratio
2 : 3
2 parts would be CHF 24
3 parts would be CHF 36
A model car is made to a scale of 1:20. The model is 12cm wide. How wide is the real-life car?
240 cm or 2.4m
7 pens cost £4.20. Find the cost of 3 pens.
£1.80
Give a real-life scenario of direct proportion.
If each book costs the same amount, the more books I buy, the more money I pay.
If y=9/x, what is the value of y when x=81?
y=1/9
There are 5 blue blocks and 10 green blocks. What is the ratio of green blocks to blue blocks?
2 : 1
A drawing of a rectangle has a scale of 1cm : 5m. The real-life rectangle has a length of 19m and a width of 7m. Find the dimensions of the scale drawing.
The width is 1.4cm and the length is 3.8cm.
A recipe for a cake for 4 people needs 150g of sugar. How much sugar is needed for a recipe for a cake for 7 people?
262.5g
If y=3x, what is the value of y when x=7?
y=21
Give a real-life example of an inverse proportion scenario.
If all workers work at the same speed, the more people I have, the less time it takes to clean a certain amount of windows.
Share 1kg in the ratio 4:6.
0.4 kg: 0.6kg or
400g : 600g
Shape B is an enlargement of shape A and both are right-angled triangles. The hypotenuse of shape A is 4cm and the hypotenuse of shape B is 8 cm. The shortest side on shape A is 1 cm. What is the length of the shortest side on shape B? Find the scale factor of the enlargement.
2cm
Scale factor: 2
132g of coffee are needed for 12 people. How many g are needed for 17 people?
187g
If y=17x, what is the value of x when y=42.5?
x=2.5
If y=17/x, what is the value of x when y=12?
x= 17/12
Zack and Kenny are waiters in a restaurant. The total amount of tips they receive at the end of the week is $126.90. Zack worked 5 nights and Kenny worked 4 nights. They decide to split the tips by the ratio of the nights they worked. How much do they get each?
Zack gets $70.50
Kenny gets $56.40
A rectangular garden measures 4m by 10m. It is drawn to a scale of 1cm:2m. Find a scale to represent the area of the real garden and the area of its scale drawing.
Area of drawing = 10cm squared
Area of garden = 40m squared or 400 000cm squared
The scale 1cm squared :4m squared or
1cm squared : 40, 000cm squared
What is the unitary method?
Find the rate for one item first and then multiply by number of items.
y is directly proportional to x. Given that y=25 when x=5, find the equation. Then solve for y when x=3.
y=5x
y=15
y is inversely proportional to the square x. Given that y=3 when x=4, find the equation. Then solve for y when x=2.
y=48/x squared
y=12