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

• 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
• 8 years agoHelpfull: Yes(29) No(1)
• 7!/3!*4!=35
• 8 years agoHelpfull: Yes(18) No(3)
• 7C3
  So ans is 35
• 8 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.
• 8 years agoHelpfull: Yes(2) No(0)
• d)
  7C4 or 7C3= 35
• 8 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!
• 8 years agoHelpfull: Yes(0) No(7)
• 7!/(3!)(5!)
• 8 years agoHelpfull: Yes(0) No(2)
• Sorry its 7!/(3!)(4!)=35
• 8 years agoHelpfull: Yes(0) No(0)
• Ans ; d) 35
• 8 years agoHelpfull: Yes(0) No(0)
• 35
  7!/(3!*4!)
• 8 years agoHelpfull: Yes(0) No(0)