The ratio of the dimensions of a model car to the dimensions of an actual car is \(1:64\). The actual car has a length of 4.9 m.
What is the length of the model car in cm, correct to 1 decimal place?
- 3.1
- 7.7
- 13.1
- 59.1
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The ratio of the dimensions of a model car to the dimensions of an actual car is \(1:64\). The actual car has a length of 4.9 m.
What is the length of the model car in cm, correct to 1 decimal place?
\(B\)
\(\text{Actual length}=4.9\ \text{m}\ =490\ \text{cm}\)
\(\therefore\ \text{Model car length}\ =490\times\dfrac{1}{64}=7.65625\approx 7.7\ \text{cm}\)
\(\Rightarrow B\)
`3.4 \ text{km/hr}`
| `text{Actual distance}` | ` =34 times 2000` | |
| `= 68\ 000 \ text{cm}` | ||
| `=680 \ text{m}` | ||
| `= 0.68 \ text{km}` |
`12 \ text{minutes}\ = 12/60 = 0.2 \ text{hours}`
| `text{Speed}` | `= text{distance}/text{time}` | |
| `= 0.68/0.2` | ||
| `= 3.4 \ text{km/hr}` |
A topographic map has a scale of 1 : 250 000.
What is the actual distance between the two lookouts, in kilometres? (1 mark)
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| i. `text{Actual distance (3.6 cm)}` | `= 3.6 xx 250\ 000` |
| `= 900\ 000\ text(cm)` | |
| `= 9\ 000\ text(m)` | |
| `= 9\ text(km)` |
`:.\ text(The 2 lookouts are 9 km apart.)`
ii. `text(Towns are 42.5 km apart.)`
`text{From the scale, } 1\ \text{cm} = 250\ 000\ \text{cm} = 2\ 500\ \text{m} = 2.5\ \text{km}`
`=>\ \text{On the map, } 42.5\ \text{km} = 42.5/2.5 = 17\ \text{cm}`
`:.\ \text{Distance on the map is 17 cm.}`
`3.9 \ text{km/hr}`
| `text{Actual distance}` | ` =26 times 3000` | |
| `= 78\ 000 \ text{cm}` | ||
| `=780 \ text{m}` | ||
| `= 0.78 \ text{km}` |
`12 \ text{minutes}\ = 12/60 = 0.2 \ text{hours}`
| `text{Speed}` | `= text{distance}/text{time}` | |
| `= 0.78/0.2` | ||
| `= 3.9 \ text{km/hr}` |
A map is drawn to scale, on 1-cm paper, showing the position of a supermarket and a cinema. A reservoir is also shown.
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With the aid of one application of the trapezoidal rule, estimate the amount of water in the reservoir immediately after the storm. Assume that all rain which falls over the reservoir is stored. Give your answer in cubic metres. (3 marks)
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a. `text(3 km/h = 3000 metres per 60 minutes)`
`text(In 10 minutes:)`
`text(Actual distance) = 3000 xx 10/60 = 500\ text(metres)`
`text(Distance on map = 5 cm)`
| `:.\ text(Scale 5 cm)` | `: 500\ text(metres)` |
| `text(1 cm)` | `: 100\ text(metres)` |
| b. |
| `A` | `~~ h/2(a + b)` |
| `~~ 400/2(100 + 300)` | |
| `~~ 80\ 000\ text(m²)` |
`text(Converting mm to metres:)`
`text(20 mm) = 20/1000 text(m = 0.02 metres)`
`:.\ text(Volume of water)`
`= A xx h`
`= 80\ 000 xx 0.02`
`= 1600\ text(m)^3`
On a map, the distance between two towns is measured at 54 millimetres.
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i. `text{Convert both distance to the same unit (cm).}`
| `text(54 mm)` | `= 5.4\ text(cm)` |
| `text(16.2 km)` | `= 16\ 200\ text(m)` |
| `= 1\ 620\ 000\ text(cm)` |
| `:.\ text(Scale) \ \ 5.4\ ` | `: 1\ 620\ 000` |
| `1\ ` | `: 300\ 000` |
| ii. | `text(Actual distance)` | `= 9.2 xx 300\ 000` |
| `= 2\ 760\ 000\ text(cm)` | ||
| `= 27\ 600\ text(m)` | ||
| `= 27.6\ text(km)` |
The scale on a given map is `1:80\ 000`.
If the actual distance between two points is 3.4 kilometres, how far apart on the map would be the two points be, in centimetres? (2 marks)
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`4.25\ text(cm)`
`text(Actual distance on map)`
`= text(real distance)/text(scale)`
`= text(3.4 km)/(80\ 000)`
`= text(3400 m)/(80\ 000)`
`= 0.0425\ text(m)`
`= 4.25\ text(cm)`
A map has a scale of 1 : 500 000.
What is the actual distance between the two mountain peaks, in kilometres? (1 mark)
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| i. `text{Actual distance (2 cm)}` | `= 2 xx 500\ 000` |
| `= 1\ 000\ 000\ text(cm)` | |
| `= 10\ 000\ text(m)` | |
| `=10\ text(km)` |
`:.\ text(The 2 mountain peaks are 10 km apart.)`
ii. `text(Cities are 75 km apart.)`
`text{From part (i), we know 2 cm = 10 km}`
`=>\ text(1 cm = 5 km)`
`=>\ text(On the map, 75 km)= 75/5=15\ text(cm)`
`:.\ text(Distance on the map is 15 cm.)`