Depends on the fifteen year old. Enough to keep him/her healthy... it is kinda relative to other variables. Make sure you have them exersize for fun... otherwise it will probably be counter productive.
1519-1521
Cortez invaded the Aztecs in 1519.
The Aztecs, and it wasn't on 1519 but on 1521.
3600 hours just kidding it is about 3500 seconds witch is 60 minutes witch is 1 hour
he was beaheaded in 1519
push ups sit ups run and all the other sports that children do
1519 when the first Spaniards landed on Mexico's shores.
During the year 1519.
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