Find the gain or loss per cent when : (i) CP=Rs. 620 and SP = Rs. 713 (ii) CP=Rs.675 and SP = Rs. 630 (iii) CP=Rs.345 and SP = Rs.372.60 : (iv) CP= Rs.80 and SP = 76.80

Answer

To find the gain or loss percentage for the given cost price (CP) and selling price (SP) values, we will follow these steps for each part of the question.

### Part (i)
**Given:**
- CP = Rs. 620
- SP = Rs. 713

**Step 1: Calculate Gain**
\[ \text{Gain} = \text{SP} - \text{CP} \]
\[ \text{Gain} = 713 - 620 = 93 \]

**Step 2: Calculate Gain Percentage**
\[ \text{Gain Percentage} = \left( \frac{\text{Gain}}{\text{CP}} \right) \times 100 \]
\[ \text{Gain Percentage} = \left( \frac{93}{620} \right) \times 100 \]
\[ \text{Gain Percentage} = 15\% \]

### Part (ii)
**Given:**
- CP = Rs. 675
- SP = Rs. 630

**Step 1: Calculate Loss**
\[ \text{Loss} = \text{CP} - \text{SP} \]
\[ \text{Loss} = 675 - 630 = 45 \]

**Step 2: Calculate Loss Percentage**
\[ \text{Loss Percentage} = \left( \frac{\text{Loss}}{\text{CP}} \right) \times 100 \]
\[ \text{Loss Percentage} = \left( \frac{45}{675} \right) \times 100 \]
\[ \text{Loss Percentage} = 6.67\% \]

### Part (iii)
**Given:**
- CP = Rs. 345
- SP = Rs. 372.60

**Step 1: Calculate Gain**
\[ \text{Gain} = \text{SP} - \text{CP} \]
\[ \text{Gain} = 372.60 - 345 = 27.60 \]

**Step 2: Calculate Gain Percentage**
\[ \text{Gain Percentage} = \left( \frac{\text{Gain}}{\text{CP}} \right) \times 100 \]
\[ \text{Gain Percentage} = \left( \frac{27.60}{345} \right) \times 100 \]
\[ \text{Gain Percentage} = 8\% \]

### Part (iv)
**Given:**
- CP = Rs. 80
- SP = Rs. 76.80

**Step 1: Calculate Loss**
\[ \text{Loss} = \text{CP} - \text{SP} \]
\[ \text{Loss} = 80 - 76.80 = 3.20 \]

**Step 2: Calculate Loss Percentage**
\[ \text{Loss Percentage} = \left( \frac{\text{Loss}}{\text{CP}} \right) \times 100 \]
\[ \text{Loss Percentage} = \left( \frac{3.20}{80} \right) \times 100 \]
\[ \text{Loss Percentage} = 4\% \]

### Summary of Results:
1. Gain Percentage for (i): 15%
2. Loss Percentage for (ii): 6.67%
3. Gain Percentage for (iii): 8%
4. Loss Percentage for (iv): 4%