Problem Solving

There are 5 cars to be displayed in 5 parking spaces with all the cars facing the same direction.
Of the 5 cars, 3 are red, 1 is blue, and 1 is yellow. If the cars are identical except for color, how
many different display arrangements of the 5 cars are possible?
A. 20
B. 25
C. 40
D. 60
E. 125

Is C not the correct answer? I got 20 as the number of arrangements if the cars are displayed in one direction. But if we reverse the direction of all cars, the total arrangements will be 20*2=40. Did I assume beyond what is stated in the problem?
OA – A

You are right, 20 is the right answer. You are not supposed to consider the cars facing in different ways, since that's exactly why you have that statement in there:

all the cars facing the same direction

That basically tells you that they share the direction and that you shouldn't worry about it. Just "worry" about the colors!

DanaJ wrote:You are right, 20 is the right answer. You are not supposed to consider the cars facing in different ways, since that's exactly why you have that statement in there:

all the cars facing the same direction

That basically tells you that they share the direction and that you shouldn't worry about it. Just "worry" about the colors!

How did you get 20?

It's 5! / 3!*1!*1!

Svedankae wrote:It's 5! / 3!*1!*1!

what is the formula for these questions?

Factorial of total # of cars/Factorial of cars that are identical.

Since there are 5 cars, factorial will be 5!
3 cars are red in color, hence 3!

5!/3! gives us 20. Hope this helps