EgmatQuantExpert wrote:

Learn structured approach to identify permutation and combination question - Exercise Question #2

How many different flags can be made from4 colors- Red, Blue, Green, and White?

Options:

A. 25

B. 24

C. 48

D. 60

E. 64

The question is incomplete the way it is..

1) I would say - " different flags from 20 m cloth if one flag is .....", so it should be different types of flags..

I am sure it means this so we can leave it here..

2) If I use two colors also, I can make 100s of different types of flags..

so the question could have been two ways..

A)

"How many different types of flags can be made from using atleast one of 4 colors- Red, Blue, Green, and White" - Without any restrictionsso a COMBINATION question..

one colour - 4 ways

two colours - 4C2 - 6 ways

three colour - 4C3 - 6 ways

four colour - 4C4 - 1 way

total = 17 ways

B)

"How many different types of flags can be made from using atleast one of 4 colors - Red, Blue, Green, and White -in horizontal stripe/vertical stripes, each coloured being used once" - With restrictionsso a PERMUTATION question..

one colour - 4 ways

two colours - 4P2 - 6*2=12 ways

three colour - 4P3 - 6*3!=24 ways

four colour - 4P4 - 4*3*2*1=24 way

total = 64 ways

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor