There are 100229 threes in the first million digits in pi.
1km = 1000m
1hr = 3600sec
Do proportions:
1km / 1000m = 15km / x
15000m = x
1hr = 3600sec
15000/3600 = 4.2m per second
Choice 4
P=2*(l+w)
p=2l+2w
2w=p - 2l
w= (p-2l)/2
2 divided by 7 would give you 29%