Since Krystal and Scott is heading on opposite
directions, therefore the distance between the two would be the sum of their
distances from where they left, so:
total distance (d) = distance covered by Krystal (dK) +
distance covered by Scott (dS)
d = dK + dS
We know that the formula for distance is:
distance = velocity * time
So,
d = vK * t + vS * t
where
vK = velocity of Krystal = 61 mph
vS = velocity of Scott = 65 mph
d = 252 miles
Therefore:
252 = 61 t + 65 t
126 t = 252
t = 2 hours
Therefore Scott needs to travel for 2 hours.
The z-score is given by:
z=(x-μ)/σ
but
x-μ=52
thus
z=52/√84681
z=0.1787
Thus:
P(X≤52)=0.9633
First, convert the distance of a typical marathon to kilometers.
1 mi = 1.609 km
26.2 miles = 42.165 km
Divide this distance by Allan's average speed to get his average time.
42.165 km / 12 km/hr = 3.514 hours
