Quantitative Aptitude MCQ - Permutation And Combinations
22
Number n of license plates that can be made where each plate contains two distinct letters followed
n = 26 x 25 x 10 x 9 x 8=468000.
i.e. there are twenty-six choices for the first letter, but only twenty-five choices for the second letter which must be different from the first letter. Similarly, choices for the digits are 10, 9 and 8 since the digits must be distinct.
Each letter can be printed in twenty-six different ways, the first digit in nine ways and each of the other two digits in ten ways. Hence 26 x 26 x 9 x 10 x 10 = 608400 different plates can be printed.
Common data for next 2 questions
Given : npr = 3024.
Since np is product of consecutive positive integers, npr=3024=9x8x7x6
Hence n=9 and r = 4
Since np is product of consecutive positive integers, npr=3024=9x8x7x6
Hence n=9 and r = 4
