How many 4 digit can be formed by using 2,3,4,5,6,7 only once divisible by 25
remember only once* divisible by
a 40
b 12
c 20
d 24

• Ans : 24
  
  For any number to be divided by 25, it should be ended with {25,50,75,100)...
  Here 0 is not in the list... so d possibilities are the numbers ended with (25 nd 75)
  
  if v take the no. to end with 25, the remaining 2 digits can be any 2 among {3,4,6,7} . so the possibities are 4!/2= 24/2= 12
  
  if v take the no. to end with 75, the remaining 2 digits can be any 2 among {2,3,4,6} . so the possibities are 4!/2= 24/2= 12
  
  so 12+12=24
• 9 years agoHelpfull: Yes(6) No(1)
• units place= 5
  tens place= 2 or 7(as tens place must have 2 or 7 to be exactly divisible by 25)
  remaining places= 3 or 4 or 6 or one from 2/5
  so total numbers formed= 3*2*2*2*1=24
• 9 years agoHelpfull: Yes(4) No(0)
• Correct ans is 20
  
  Soln
  
  
  - - - -
  
  unit place can be filled in 1 way using 5
  
  tens place can be filled in 2 ways uing 2 or 7 in order to make it divisible by 25 exactly once
  
  hundred and thousand place can be filled in 4 and 3 ways using remainin digits
  
  Total no = 24
  
  Now , here we have include no of the form X625 where X= 3,4,7
  Thus these 3 numbers must be subtracted
  
  Also 625 * 7 = 4375 is include above and hence must be subtracted
  
  Hence the total number of digits = 24-4 = 20 ANS
• 9 years agoHelpfull: Yes(4) No(7)
• 24, unit place must be 5, and 10's place must be 2 or 7, then remaining digits are either (2,3,4,6) or (3,4,6,7).
• 9 years agoHelpfull: Yes(2) No(0)
• yeah 24 it is... but in the remaining places it should be 3 or 4 or 6 or one from 2/7 not 5... as 5 must present at units place
• 9 years agoHelpfull: Yes(1) No(0)
• Unit place should be 5 here & to make it divisible by 25 tens place should be either 2 or 7.
  As multiple of 25 are 25,50,75,100,..,175,..225 like this
  Now if last two digit 2 & 5 , rest of two digits are selected from 4 digit(3,4,6,7)
  So the total number of digits which contain 25 as their last two digits are:- 4P2*1!*1!=12
  In the same way when the last two digit is 75, the total number of digit should be 12 ( according to the previous logic)
  Hence total no of digits= 12+12=24..
• 9 years agoHelpfull: Yes(1) No(0)
• ans 24.
  when 2 is in tens place we got total= 4*3*1*1=12 ways
  
  when 7 is in tens place we got total= 4*3*1*1=12 ways
  
  12+12=24
• 9 years agoHelpfull: Yes(1) No(0)
• units place= 5
  tens place= 2 or 7(as tens place must have 2 or 7 to be exactly divisible by 25)
  remaining places= 3 or 4 or 6
  so total numbers formed= 3*2*1*2*1=12
• 9 years agoHelpfull: Yes(0) No(5)
• What about 275 and 725 in the last three digits
  @ritesh sharma
  In my view the possibilities in ends
  25, 75, 275, 325, 375, 425, 475, 625, 675, 725.
  For 25 and 75----------4p2*2=12
  For remain 8-----------3*8=24
  Total 36
• 9 years agoHelpfull: Yes(0) No(1)