Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is
(a)15
(b)16
(c)18
(d)25

Options

A. 15
B. 16
C. 18
D. 25

Answer

To solve the problem, we need to determine how many days Tanya will take to complete the same piece of work that Sakshi can do in 20 days, given that Tanya is 25% more efficient than Sakshi.

### Step-by-Step Solution:

1. **Determine Sakshi's Efficiency:**
- Sakshi can complete the work in 20 days.
- Therefore, Sakshi's work efficiency can be calculated as:
\[ \text{Efficiency of Sakshi} = \frac{1 \text{ work}}{20 \text{ days}} = \frac{1}{20} \text{ work per day} \]

**Hint:** Efficiency is calculated as the total work divided by the number of days taken to complete that work.

2. **Calculate Tanya's Efficiency:**
- Tanya is 25% more efficient than Sakshi.
- To find Tanya's efficiency, we first calculate 25% of Sakshi's efficiency:
\[ 25\% \text{ of Sakshi's efficiency} = 0.25 \times \frac{1}{20} = \frac{1}{80} \]
- Now, we add this to Sakshi's efficiency to find Tanya's efficiency:
\[ \text{Efficiency of Tanya} = \frac{1}{20} + \frac{1}{80} \]
- To add these fractions, we need a common denominator (which is 80):
\[ \frac{1}{20} = \frac{4}{80} \quad \text{(since } 20 \times 4 = 80\text{)} \]
- Now we can add:
\[ \text{Efficiency of Tanya} = \frac{4}{80} + \frac{1}{80} = \frac{5}{80} = \frac{1}{16} \text{ work per day} \]

**Hint:** When adding fractions, ensure you have a common denominator.

3. **Calculate the Number of Days Tanya Takes:**
- Since Tanya's efficiency is \(\frac{1}{16}\) work per day, the number of days Tanya will take to complete the work is the reciprocal of her efficiency:
\[ \text{Days taken by Tanya} = \frac{1 \text{ work}}{\frac{1}{16} \text{ work per day}} = 16 \text{ days} \]

**Hint:** The number of days taken to complete a work is the inverse of the efficiency.

### Conclusion:
Thus, the number of days taken by Tanya to do the same piece of work is **16 days**.

### Final Answer:
(b) 16