Reena borrowed from Kamal certain sum for two years at simple interest. Reena lent this sum to Hamid at the same rate for two years compound interest. At the end of two years she received Rs 110 as compound interest but paid Rs 100 as simple interest. Find the sum and rate of interest.

Explanation

To solve the problem step by step, we will first define the variables and then use the information given in the problem to find the sum borrowed and the rate of interest.

### Step 1: Define Variables
Let:
- \( P \) = Principal amount (the sum borrowed by Reena)
- \( R \) = Rate of interest (in percentage)
- \( N \) = Number of years = 2

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