50 miles ... 60 minutes
15 miles ... x minutes
If you would like to know how long would it take an ostrich to run 15 miles, you can calculate this using the following steps:
50 * x = 15 * 60
50 * x = 900 /50
x = 900 / 50
x = 18 minutes
Result: An ostrich can run 15 miles in 18 minutes.