Foundation June 2021 Paper 1 Q13
13 Buses leave a bus station to go to the hospital every 16 minutes.
Buses leave the same bus station to go to the college every 20 minutes.
At 9 am a bus leaves the bus station to go to the hospital and at the same time a bus leaves the bus station to go to the college.
Work out the next time that a bus leaves the bus station to go to the hospital and at the same time a bus leaves the bus station to go to the college.
(3)
| Scheme | Marks |
|---|---|
| 16, 32, 48,… and 20, 40, 60… or [9] 16, [9] 32, [9] 48, ….. and [9] 20, [9] 40, [9] 60 (or 10), ….. or 2, 2, 2, 2 or 2, 2, 5 or a Venn diagram of prime factors: 2, 2 in one circle only, 2, 2 in the overlap and 5 in the other circle only | M1 |
| 16, 32, 48, 64, 80 and 20, 40, 60, 80 or [9] 16, [9] 32, [9] 48, [10] 04, [10] 20 and [9] 20, [9] 40, [9] 60 (or 10), [10] 20 or 2 × 2 × 2 × 2 × 5 (= 80) or \(2^4 \times 5\) (= 80) | M1 |
| Working not required, so correct answer scores full marks (unless from obvious incorrect working) Answer: 10 20 | A1 |
| (3) | |
| (3 marks) |
Notes
M1: for any correct valid method e.g.
for starting to list at least three multiples of each number (allow one error (ft eg 16, 34, 50) in one list)
or 2, 2, 2, 2 or 2, 2, 5 seen (may be in a factor tree and ignore 1)
or for a Venn diagram with correct factors for one of 16 or 20
M1: for a correct method leading to 80 or the correct time (all working must be correct for the award of this mark) or for stating 80
A1: 10 20 or 10 20 am or twenty past ten oe