It would be 6 miles per hour.
mph is a unit for speed. And the formula for speed is s=distance /time
So the distance is 2 miles
And the time is 20 minutes
*for this question you need to convert the minutes to hours to get the right units
20mins =0.3 hours (approx) [20/60 to get it in hours]
2 miles/0.3 hours ≈ 6 mph
This can be solved by using the normal approximation to the binomial distribution.
mean = np = 10.000 * 0.5 = 5,000
The standard deviation is given by:


The probability of obtaining more than 5100 tails is 0.0228 and the probability of obtaining fewer than 5100 tails is 0.9772.
The odds of obtaining more than 5100 tails is therefore:
0.0228:0.9772 = 1:42.86.
Have fun but I think it is b and e