Simple Interest Work Graph
1. **Problem (01a):** Suman took a loan of 60000 at an 18% annual simple interest rate to be paid in 3 years.
(i) Find the interest for 1 year.
**Step 1:** Simple interest for 1 year is calculated as $I = P \times R \times T$, where $T$ is in years.
Here, $P = 60000$, $R = 18\% = 0.18$, $T=1$ year.
$$I = 60000 \times 0.18 \times 1 = 10800$$
(ii) Find total amount to be paid at end of 3 years.
**Step 2:** Total simple interest for 3 years is:
$$I_{total} = 60000 \times 0.18 \times 3 = 32400$$
**Step 3:** Total amount = Principal + Interest:
$$A = 60000 + 32400 = 92400$$
(iii) Find monthly instalments if paid equally including interest.
**Step 4:** Number of months = $3 \times 12 = 36$
**Step 5:** Monthly instalment = Total amount / Number of months
$$\text{Monthly instalment} = \frac{92400}{36} = 2566.67$$
2. **Problem (01b):** 12 men complete work in 10 days. 2 days after starting, 4 men leave. Find how many more days needed.
**Step 1:** Total work = $12 \times 10 = 120$ man-days.
**Step 2:** Work done in first 2 days by 12 men:
$$12 \times 2 = 24$$ man-days.
**Step 3:** Remaining work:
$$120 - 24 = 96$$ man-days.
**Step 4:** Remaining men = 12 - 4 = 8 men.
**Step 5:** Days needed to complete remaining work:
$$\text{Days} = \frac{\text{Remaining work}}{\text{Remaining men}} = \frac{96}{8} = 12$$ days.
3. **Problem (02a)(i):** Evaluate $y$ at $x=1$ for $y = 2x^2 - 3$.
Substitute $x=1$,
$$y = 2(1)^2 - 3 = 2 - 3 = -1$$
4. **Problem (02b)(i):** Find minimum value of $y = 2x^2 -3$.
**Step 1:** The quadratic opens upwards (coefficient of $x^2$ is positive), so minimum at vertex.
**Step 2:** Vertex $x = -\frac{b}{2a} = -\frac{0}{2 \times 2} = 0$.
**Step 3:** Minimum value:
$$y_{min} = 2(0)^2 - 3 = -3$$
5. **Problem (02b)(iii):** Find roots of equation $2x^2 - 3 = 0$.
**Step 1:** Solve for $x$:
$$2x^2 = 3$$
$$x^2 = \frac{3}{2}$$
**Step 2:** Roots:
$$x = \pm \sqrt{\frac{3}{2}} = \pm \frac{\sqrt{6}}{2}$$
**Answers:**
(i) Interest for 1 year = 10800
(ii) Total amount = 92400
(iii) Monthly instalment = 2566.67
(iv) Additional days needed = 12
(v) $y$ at $x=1$ is $-1$
(vi) Minimum value = $-3$
(vii) Roots are $x = \pm \frac{\sqrt{6}}{2}$