For A it's simply asking how far Jo has walked after 10 minutes. So A is 1km.
For B I believe it's asking for how many miles Jo will walk per hour for the speed.
So, 1km is 0.6 miles; so in 30 minutes Jo has walked 4km. So 4km is 2.5 miles.
So, in 1 hour Jo would walk for 5 miles.
So for B, Jo is walking at 5 miles per hour.
B) 5 miles per hour
Hope you understand my writing as I sometimes go off on a tangent and my writing ends up making sense only to me
Have a nice day