SOLUTION: How many 4 digit numbers can be formed out of the digits (3,4,5,6,7)which are greater than 5000 and no digit is repeated.the options are
a)72(correct)
b)27
c)70
d)none of these
Question 1031304: How many 4 digit numbers can be formed out of the digits (3,4,5,6,7)which are greater than 5000 and no digit is repeated.the options are
a)72(correct)
b)27
c)70
d)none of these
I tried to solve it in the following way
if it is a 4 digit number greater than 5000 then the first number can be 5,6 or 7 so we have three choices
the second digit can be any of the above numbers(3,4,5,6,7)so we have 5 choices as no digit can be repeated we are left with 4 and 3 choices for the 3rd and 4th digit respectively
we can summarize it with the help of the fundamental principle of counting as
3*5*4*3=180
but this is wrong,
the correct answer is 72
please reply as soon as possible
thank you
yours sincerely
sukhdeep
1. Any of three numbers (5, 6, 7) in the first (from the left) position;
2. any of 4 remaining numbers in the second position;
3. any of 3 remaining numbers in the third position;
4. any of 2 remaining numbers in the fourth position.
3*4*3*2 = 72.