Answer:
55mph
Explanation:
car A distance, d1= 220
car b distance, d2= 260
speed of car A, s1= speed of car B- 10
let speed of car B be s2
s1= s2-10
speed = distance/time
time= distance/speed
As time of car A= time of car B
distance of Car A/speed of Car A=distance of Car B/speed of Car B
220/s2-10= 260/s2
s2=(s2-10)260/220
s2=65
s1= s2- 10
= 65-10
=55
hence speed of first car is 55mph !