distance= 112 miles apart
time = 4 hours
Speed of a = 3 *speed of b
Distance covered by a = 3 * distance covered by b
Speed = distance / time
3b+b = 112
4b = 112
b= 112/4
b= 28 miles
a = 3b
a = 3 *28
a= 84 miles
Since both travelled for 4 hours:
Speed of A = 84 /4 = 21 mph
Speed of b= 28 /4 = 7 mph
Speed of the faster cyclist : 21 mph