Probability is the event happening divided by the total events
The event that must be happen is Sarah and Janet will drive a red number car.
We have 2 red cars, 3 green cars and 3 blue cars, a total of 8 events
The probability that Sarah will drive a red car is 2/8
Now we have 7 cars left to choose from and 1 of it is a red car.
The probability that Janet will drive a red car is 1/7
Multiply the two probabilities.
In percentage :
0.036 x 100 = 3.6%
The answer is 3.6%