Uranium ores on the earth at the present time typically have a composition consisting of `99.3%` of the isotope `._92U^238` and `0.7%` of the isotope `._92U^235`. The half-lives of these isotopes are `4.47xx10^9yr` and `7.04xx10^8yr`, respectively. If these isotopes were equally abundant when the earth was formed, estimate the age of the earth.

Explanation

To estimate the age of the Earth using the isotopes of uranium, we can follow these steps:

### Step 1: Understand the Composition of Uranium Isotopes
We know that the current composition of uranium isotopes in the Earth is:
- \( 99.3\% \) of \( _{92}^{238}U \) (Uranium-238)
- \( 0.7\% \) of \( _{92}^{235}U \) (Uranium-235)

### Step 2: Determine the Half-Lives of the Isotopes
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