Mia’s average driving speed is 6 kilometers per hour faster than Kirk’s. In the same length of time it takes Mia to drive 558 kilometers, Kirk drives only 522 kilometers. What is Mia’s average speed?

Respuesta :

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