Question 973618
Mean = t   sd= s

we know that half the runners finished in less than some mean time

we know that 16%  runners finished in fewer than 3.725 hours, 1 sd below the mean.  This makes the mean greater than 3.725 hours.

we also know that 2.5% runners finished in fewer than 2.915 hours.  1.96 sd below the mean

Therefore, 0.810 hours is 0.96 sd; therefore 0.844 hours must be the standard deviation.

That makes the mean 4.569 hours. ;;;    That is 4 hours 34 minutes and 8 seconds.

The standard deviation is 50 m 38 s.