Reading scales — Notes & Worked Examples Show / Hide
Explanation:
To read any scale accurately, never guess what each small mark goes up in. First find the difference between two neighbouring numbered marks, then count the number of spaces (divisions) between them (count the gaps, not the tick lines).
Divide the difference by the number of gaps: 1 small division = Gap ÷ Number of spaces. Also check whether the question asks you to convert units (e.g. 1 kg = 1000 g, 1 litre = 1000 ml).
Example 1: Write down the reading shown by the arrow on this kitchen scale.
Example 2: A jug has 10 divisions between 1.5 L and 2.0 L. Water is 7 divisions above 1.5 L. Find the volume in L and ml.
Worked Solution & Answer
3.5 cm
Identify the two correct statements from the list:
1. ABĈ is not equal to CDÂ
2. AB = DC and AD = BC and AC is a side of both triangle ABC and triangle CDA
3. Triangle ABC is similar to triangle CDA with enlargement scale factor 0.5
4. Triangle ABC is not congruent to triangle CDA
5. Triangle ABC is congruent to triangle CDA
6. AB represents the shortest distance from B to AC
Worked Solution & Answer
He weighs his suitcase on the weighing scales at the airport.
The reading on the scale gives the weight of Amir's suitcase.
This charge is 7.45 euros for each kilogram over the 25 kg limit.
Work out the excess luggage charge that Amir has to pay.
Worked Solution & Answer
Excess weight = 36 – 25 = 11 kg M1
Charge = 11 × 7.45 = 81.95 euros. A1
The tree and the man are drawn to the same scale.
Worked Solution & Answer
Rhian needs to score 7 or more with a single spin to win the game.
On the probability scale below, mark with an arrow the probability that Rhian wins the game.
(b) Tomas is playing a game with a different fair spinner.
Here is the shape of his spinner.
The arrow on the probability scale below shows the probability that Tomas scores less than 4 with one spin.
Write five numbers on Tomas' spinner so that the scale is correct.
(c) Simon is playing a game.
The probability that he wins the game is (0.7).
What is the probability that Simon does not win his game?
Rhian needs to score 7 or more with a single spin to win the game. [1 mark]
Here is the shape of his spinner.
The arrow on the probability scale below shows the probability that Tomas scores less than 4 with one spin.
Write five numbers on Tomas' spinner so that the scale is correct. [1 mark]
What is the probability that Simon does not win his game? [1 mark]
Worked Solution & Answer
Probability = 28 = 14. B1
Therefore, exactly 2 of the 5 numbers on the spinner must be less than 4. B1
What is the total mass of two apples and two pears? [3 marks]
Worked Solution & Answer
Mass of 1 apple = 450 ÷ 3 = 150 g. B1
Mass of 1 pear = 450 ÷ 5 = 90 g
Mass of 2 apples = 2 × 150 = 300 g M1
Mass of 2 pears = 2 × 90 = 180 g
Total mass = 300 + 180 = 480 g. A1
Worked Solution & Answer
Worked Solution & Answer
Impossible Unlikely Even chance Likely Certain
(a) (ii) A dish contains equal numbers of green grapes and black grapes.
Pedro takes one grape at random from the dish.
Circle the best expression for the chance that Pedro takes a green grape:
Impossible Unlikely Even chance Likely Certain
(b) (i) One letter is chosen at random from the 9-letter word AUSTRALIA.
On the probability scale below, mark with an arrow (\downarrow) the probability that the letter chosen from the word AUSTRALIA is T.
(b) (ii) A, E, I, O, U are vowels.
On the probability scale below, mark with an arrow (\downarrow) the probability that the letter chosen from the word AUSTRALIA is a vowel.
Impossible Unlikely Even chance Likely Certain [1 mark]
Pedro takes one grape at random from the dish.
Circle the best expression for the chance that Pedro takes a green grape:
Impossible Unlikely Even chance Likely Certain [1 mark]
On the probability scale below, mark with an arrow (\downarrow) the probability that the letter chosen from the word AUSTRALIA is T. [1 mark]
On the probability scale below, mark with an arrow (\downarrow) the probability that the letter chosen from the word AUSTRALIA is a vowel. [1 mark]