Radiometric Dating Question?

Let's say we find a mineral that should have contained uranium when it formed, but should not have contained any lead. We take this mineral into the labratory and measure the amount of uranium-235 and lead-207 in this mineral. We find that it contains 62.5 grams of uranium-235 and 937.5 grams of lead-207. uming that there are no problems with the measurement and that all of the lead results from radioactive decay, how old is that mineral?