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[tanmaydube]

Find how many different odd 4-digit numbers less than 4000 can be made from the digits 1, 2, 3, 4, 5, 6, 7 if no digit may be repeated.
question of permutation and combination

 

[destined007]

 

[tanmaydube]

i can't get these three questions mate

15. Find the total number of different arrangements, taking all the letters at the same time, of the letters of the word MATHEMATICAL.

16. Calculate the number of different arrangements, taking all the letters at the same time, of the letters in the word “CONCLUDE”. How many of these arrangements
(a) have all the consonants together?
(b) begin with a consonant and end with a vowel?
(c) have the vowels together?

17. Jacob has four choices of travelling to school everyday; he can walk, cycle, take a feeder bus service or the MRT. In how many ways he can arrange his mode of transport for the next three days?

 

[Nikesh]

15. its 12factorial /(2factorial * 3factorial * 2factorial )

 

[Nikesh]

i can't get these three questions mate

15. Find the total number of different arrangements, taking all the letters at the same time, of the letters of the word MATHEMATICAL.

16. Calculate the number of different arrangements, taking all the letters at the same time, of the letters in the word “CONCLUDE”. How many of these arrangements
(a) have all the consonants together?
(b) begin with a consonant and end with a vowel?
(c) have the vowels together?

17. Jacob has four choices of travelling to school everyday; he can walk, cycle, take a feeder bus service or the MRT. In how many ways he can arrange his mode of transport for the next three days?

16. 8factorial /2factorial
a. assume all consonants to be a single one i.e. CNCLD as X
i.e. the word becomes XOUE
now total arrangements = 4!/2! (since C is repeated in X)
b and c are similar to this

17. Question is not so clear but i think its answer is 3 * 4C1