Question 65980
Speed of Martina = 24 mph
So distance covered by her in 2 hrs = 24*2
                                    = 48 miles
==> at 11 A.M., Martina is 48 miles away from John.

Speed of John = 48 mph

Let us say the they both meet after x hrs after John's departure.

Distance travelled by Martina in x hrs = 24x + 48

Distance travelled by John in x hrs = 48x

As they meet , they would have travelled the same distance.

==> 48x = 24x + 48
==> 48x - 24x = 48
==> 24x = 48
==> 24x/24 = 48/24
==> x = 2

==> they meet after 2hrs after John's departure.
==> they meet at 11 A.M., + 2hrs
              at 1 P.M

Thus John catches up with Martina at 1 P.M



Good Luck!!!