How many square millimetres are in 0.004 square metres?
- 4
- 40
- 4000
- 40 000
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How many square millimetres are in 0.004 square metres?
`D`
| `text{Since 1 m}^2` | `= 1000\ text{mm} xx 1000\ text{mm}` |
| `= 1\ 000\ 000\ \text{mm}^2` |
`:. 0.004\ \text{m}^2= 0.004 xx 1\ 000\ 000= 4000\ \text{mm}^2`
`⇒ D`
Sarah jogs at a speed of 18 km/h.
What is this speed in m/s?
`B`
| `text(18 km/h)` | `= 18\ 000\ text(metres per hour)` |
| `= (18\ 000)/60\ text(metres per minute)` | |
| `= (18\ 000)/(60 xx 60)\ text(metres per second)` | |
| `=5\ text(m/s)` |
`=> B`
During a study break, Sam is walking while Alex is sitting.
Sam breathes in air at a rate of 30 litres per minute while walking. Alex breathes in air at a rate of 8 litres per minute while sitting.
During a 20-minute break, how much more air would Sam breathe than Alex?
`=>\ B`
| `text{Sam’s total}` | `= 30 × 20 = 600\ \text{L}` |
| `text{Alex’s total}` | `= 8 × 20 = 160\ \text{L}` |
| `text{Difference}` | `= 600 − 160 = 440\ \text{L}` |
`=>\ B`
Peter rides his bike at a speed of 27 km/h.
What is this speed in m/s?
`A`
| `text(27 km/h)` | `= 27\ 000\ text(metres per hour)` |
| `= (27\ 000)/60\ text(metres per minute)` | |
| `= (27\ 000)/(60 xx 60)\ text(metres per second)` | |
| `=7.5\ text(m/s)` |
`=> A`
During a ten-minute period, Kath is exercising and Jim is resting.
How much more air would Kath breathe than Jim during this time?
`C`
`text(Kath’s air volume)= 10 xx 100=1000\ text(L)`
`text(Jim’s air volume)= 10 xx 6= 60\ text(L)`
`:.\ text(Extra air that Kath breathes)= 1000-60= 940\ text(L)`
`=> C`
How many square centimetres are in 0.0075 square metres?
`C`
`text{Since 1 m}^2= 100\ text(cm) xx 100\ text(cm)= 10\ 000\ text{cm}^2`
`:.0.0075\ text{m}^2= 0.0075 xx 10\ 000= 75\ text{cm}^2`
`=> C`
Bhawana purchases pool chlorine in a new container which holds 35 kg.
She begins using this new container on the first day of a week.
How many full weeks should this container last? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
`text(15 full weeks.)`
`text(Cups used per week)= 3 + 6 = 9`
`text(Chlorine usage per week)= 9 xx 250text(g)= 2250 text(g)`
`text(Total chlorine available)\ = 35text(kg) = 35\ 000\ text(grams)`
`text(Time it will last)= (35\ 000)/2250= 15.555…`
`:.\ text(The container will last 15 full weeks.)`