A-LevelMathematicsProbability and statistics9709/61 · May/June 2025 · Q46 Marks
At an entertainment centre, the cost for using a particular video game is $0.40 per minute. The number of minutes for which people use the video game has mean 15 and variance 9.
- (a)Find the mean and variance of the amount people pay for using the video game.[3]
- (b)Find the mean and variance of the total amount paid by 35 people.[3]
Mark scheme
Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.
- [B1] Mean = 6 [$] Ignore units in both parts of question 4.
- [M1] Variance = 0.40^2 × 9
- [A1] = 1.44 [$^2]
- [B1FT] Mean = 35 × '6' = 210 [$] FT their mean in 4(a)
- [M1] Variance = 35 × '1.44'
- [A1] = 50.4 [$^2]
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →