NAPLAN Numeracy Year 9 Practice Flashcards

A bag contains 5 red marbles, 3 blue marbles and 2 green marbles. If one marble is chosen at random, what is the probability of choosing a red marble?

Answer: 1/2

Total marbles = 10. P(red) = 5/10 = 1/2

A sequence of figures is made with matchsticks: Figure 1 uses 4, Figure 2 uses 7, Figure 3 uses 10. How many matchsticks are needed for Figure 8?

Answer: 25

Rule: 3n + 1. Figure 8 = 3(8) + 1 = 25

A car travels 360 km using 45 litres of petrol. What is the car's fuel efficiency in kilometres per litre?

Answer: 8 km/L

Fuel efficiency = 360 ÷ 45 = 8 km/L

A stem-and-leaf plot shows quiz scores: Stem 5: leaves 2 4 7 Stem 6: leaves 1 3 3 8 Stem 7: leaves 0 5 9 Stem 8: leaves 2 6 What is the median score?

Answer: 65

12 values in order: 52,54,57,61,63,63,68,70,75,79,82,86. Median = (63+68)/2 = 65.5 ≈ 65

A rectangular block of wood measures 8 cm × 5 cm × 3 cm. What is its total surface area?

Answer: 158 cm²

SA = 2(8×5 + 8×3 + 5×3) = 2(40+24+15) = 2×79 = 158 cm²

In a class of 30 students, the ratio of boys to girls is 2 : 3. How many girls are in the class?

Answer: 18

Total parts = 5. Girls = (3/5) × 30 = 18

A straight angle is divided into three parts. Two of the angles are 47° and 65°. What is the third angle?

Answer: 68°

Straight angle = 180°. Third angle = 180 − 47 − 65 = 68°