we know that
Monica can walk 3.8 kilometers in 40 minutes
and
she can jog twice that distance in the same amount of time
that means
in 40 minutes Monica can jog (3.8 km*2)-----> 7.6 km
1 hour=60 minutes
by proportion
7.6 km/40 minutes=x km/60 minutes
x=7.6*60/40----> x=11.4 km
the answer is
11.4 km