How many different (mutually noncongruent ) trapeziums can be constructed using four distinct side lengths from the set {1,3,4,5,6} ?

Five different digits from the setoff numbers {1,2,3,4,5,6,7} are written in random order. How many numbers can be formed using 5 different digits from set {1,2,3,4,5,6,7} if the number is divisible by 9?

Five different digits from the setoff numbers {1,2,3,4,5,6,7} are written in random order. How many numbers can be formed using 5 different digits from set {1,2,3,4,5,6,7} if the number is divisible by 9?

Five different digits from the setoff numbers {1,2,3,4,5,6,7} are written in random order. How many numbers can be formed using 5 different digits from set {1,2,3,4,5,6,7} if the number is divisible by 9?

How many different four-digit numbers greater than 6000 can be formed using the digit 1,2,4,5,6,7, if no digit can be repeated ?

How many words of four letter can be constructed by using the letters of the words CHEMISTRY(may not be meaningful)?

How many different four-digit numbers greater than 6000 can be formed using the digit 1,2,4,5,6,7, if repetitions are allowed ?

How many different signals can be given using any number of flags from 5 flags of different colors?