Answer:
93km/hr
Step-by-step explanation:
Using the formula Speed = Distance/Time. From the formula we can substitute for time as shown;
Time = Distance/Speed
Let the distance and speed travelled by Mia be Dm ans Ds respectively
Distance travelled by Kirk be Km and and Ks respective.
Time taken be Mia to travel Tm = Dm/Sm
Time taken be Kirk to travel Tk = Dk/Sk
Since it takes the same length of time for both of them to travel, then Tm = Tk. Hence Dm/Sm = Dk/Sk
Given parameters
Dm = 558 kilometers
Dk = 522 kilometres
If Mia’s average driving speed is 6 kilometers per hour faster than Kirk’s, then Mia's driving speed Sm = 6 + Sk
Required
Mia’s average speed (Sm)
Since Dm/Sm = Dk/Sk
Substituting the given values to get Sk first we have;
558/6+Sk = 522/Sk
Cross multiply
558Sk = 522(6+Sk)
open the parenthesis
558Sk = 3132 + 522SK
558Sk-522Sk = 3312
36Sk =3132
Sk = 3132/36
Sk =87km/hr
SInce Sm = 6+Sk
Sm = 6+87
Sm = 93km/hr
Hence Mia's average speed is 93km/hr