Probability Bearing Graph
1. **State the problems:**
- (ii) Write the sample space $S$.
- (iii) Write the elements of $A$ and find $n(A)$.
- (iv) Find the probability $p(A)$ of event $A$.
- (v) Find the probability of obtaining a number not less than three.
- Bearing and distance problems related to a scale diagram.
- Complete the table for $y=3x-2$ and draw its graph.
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2. **Sample space $S$:**
The sample space $S$ is the set of all possible outcomes. Given:
$$S = \{1, 2, 3, 4, 5, 6, 7\}$$
Number of elements in $S$ is $n(S) = 7$.
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3. **Event $A$ and $n(A)$:**
Given:
$$A = \{1, 2, 3, 4, 5, 6, 7\}$$
Number of elements in $A$ is:
$$n(A) = 7$$
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4. **Probability of event $A$:**
Probability formula:
$$p(A) = \frac{n(A)}{n(S)}$$
Since $A = S$, then:
$$p(A) = \frac{7}{7} = 1$$
This means event $A$ is certain.
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5. **Probability of obtaining a number not less than three:**
Numbers not less than 3 are $\{3,4,5,6,7\}$.
Number of favorable outcomes:
$$n = 5$$
Probability:
$$p = \frac{5}{7}$$
The user states $\frac{4}{7}$, but correct count is 5 numbers, so probability is $\frac{5}{7}$.
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6. **Bearing and distance problems:**
(i) Instrument to find bearing: **clinometer**.
(ii) Bearing of office from gate is not numerically given, but can be found from the diagram (not provided here).
(iii) Scale diagram with scale 1:10 means 1 cm represents 10 m.
(iv) Using scale diagram, measure distance and bearing to Science Lab from gate.
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7. **Triangle data:**
- Gate to Office: 60 m, angle at Office 50°.
- Gate to Science Lab: 80 m, angle at Gate 50°.
Use Law of Cosines or Sines to find distance Office to Science Lab and bearing.
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8. **Complete the table for $y=3x-2$:**
Given:
| x | -1 | 0 | 1 | 2 | 3 |
|---|----|---|---|---|---|
| y | ? | ? | ? | ? | ? |
Calculate each:
- $y(-1) = 3(-1) - 2 = -3 - 2 = -5$
- $y(0) = 3(0) - 2 = 0 - 2 = -2$
- $y(1) = 3(1) - 2 = 3 - 2 = 1$
- $y(2) = 3(2) - 2 = 6 - 2 = 4$
- $y(3) = 3(3) - 2 = 9 - 2 = 7$
Table completed:
| x | -1 | 0 | 1 | 2 | 3 |
|---|----|---|---|---|---|
| y | -5 | -2| 1 | 4 | 7 |
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9. **Graph of $y=3x-2$:**
- Plot points from table.
- Draw straight line through points.
- This is a linear function with slope 3 and y-intercept -2.
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**Final answers:**
- Sample space $S = \{1,2,3,4,5,6,7\}$, $n(S)=7$.
- Event $A = \{1,2,3,4,5,6,7\}$, $n(A)=7$.
- $p(A) = 1$.
- Probability of number $\geq 3$ is $\frac{5}{7}$.
- Instrument: clinometer.
- Table for $y=3x-2$ completed as above.