Find the number of half lives elapsed, before which, 93.75% of a radioactive sample has decayed.

Explanation

To solve the problem of finding the number of half-lives elapsed before 93.75% of a radioactive sample has decayed, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Problem**: We need to find how many half-lives it takes for 93.75% of a radioactive sample to decay. This means that only 6.25% of the original sample remains.

2. **Set Up the Equation**: The remaining quantity of a radioactive sample after a certain number of half-lives can be expressed as:
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