Elitmus
Exam
Numerical Ability
Number System
how many 7 digit number are there having the digit 3 three times & the digit 5 four times?
a) 7!/(3!)(5!)
b) 3^3 * 5^5
c) 77
d) 35
Read Solution (Total 11)
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- Total Way we can form the number of 7 digit is 7!
but condition is given 3 repeat in 3 times and 5 repeats four time means(3,3,3) and (5,5,5)
(3,3,3) can arrange in 3 ways so 3!
(5,5,5,5) can arrange in 4 ways so 4!
Hence 7!/3!4!=35 - 9 years agoHelpfull: Yes(29) No(1)
- 7!/3!*4!=35
- 9 years agoHelpfull: Yes(18) No(3)
- 7C3
So ans is 35 - 9 years agoHelpfull: Yes(5) No(5)
- here no. is the seven digit . In this no. two type no. are present like 3335555 .so , n!=7! nd one is 3! and another type is 4! hence we can write it like ....7!/3!4! . dis equals to 35.
- 9 years agoHelpfull: Yes(2) No(0)
- d)
7C4 or 7C3= 35 - 9 years agoHelpfull: Yes(1) No(0)
- Such simple questions will not be asked in elitmus. I don't think it was really asked in pH test.
- 7 years agoHelpfull: Yes(1) No(0)
- total ways=7!
but 3 is three times and 5 is four times
so
7!/3!*5! - 9 years agoHelpfull: Yes(0) No(7)
- 7!/(3!)(5!)
- 9 years agoHelpfull: Yes(0) No(2)
- Sorry its 7!/(3!)(4!)=35
- 9 years agoHelpfull: Yes(0) No(0)
- Ans ; d) 35
- 9 years agoHelpfull: Yes(0) No(0)
- 35
7!/(3!*4!) - 9 years agoHelpfull: Yes(0) No(0)
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