Q. HOW MANY 4 DIGIT NO.CAN BE MADE WITH THE DIGITS 1,2,3,4,5,6,7 DIVISIBLE BY 25 ONLY ONCE?

Option
a) 20
b) 24
c) 60
d) Cant be determined

• only the digits ending with 25 and 75 are divisible by 25.
  So, 5 should occupy the one's place (1)
  either 2 or 7 should occupy the 10's place. 2
  from the remaining numbers 1236(2 or 7) occupy 100's place. 5
  and then in thousand's place 4
  so, 4*5*2*1=40;
• 11 years agoHelpfull: Yes(27) No(21)
• DIVISIBLE BY 25 ONLY ONCE means?
  some digits 3125,4375 are divisible by 25 twice
  so 40 cant be answer
  ans 24
  (b)
  
• 11 years agoHelpfull: Yes(27) No(12)
• DIGITS are 1,2,3,4,5,6,7
  so no. is divisible by 25 only when last two digit is 25 or 75
  DIVISIBLE BY 25 ONLY ONCE = TOTAL NO. DIVISIBLE BY 25 - NO. DIVISIBLE BY 625
  =5*4*2*1-4*1
  =40-4
  =36
• 11 years agoHelpfull: Yes(9) No(3)
• nums divisible by 25 are 40 as we all know
  nums divisible by 625 are:
  ----
  units place is always 5----1 way
  tens place can be 5,2,7..but 5 is already in units place..so it can be filled with 2 or 7 in---2 ways
  hundreds place can be with 1,5,7..but 5 is already in units place..so it can be filled with 1 or 7 in---2 ways
  thousands place in 4c1 ways..i.e 4 ways..
  total 4*2*2=16
  overall 40-16=24
• 11 years agoHelpfull: Yes(6) No(1)
• the ans would be 24(b). as the question says the num should be divisible by 25 only once that means it should not be divisible by 25*25 i.e. 625. so the ans will be obtained by( numbers div by 25- numb div by 625) i.e. 40-16=24
• 11 years agoHelpfull: Yes(5) No(2)
• to divide by 25 u must have 25,75 or 50 at right most side. so for right most position only one no. 5, for 10th position 2 or 7,100th-any of remaining 5 and 1000th only 4
  so solution is 4*5*2*1=40
• 11 years agoHelpfull: Yes(4) No(5)
• its 20..
  40-(the 4digit no. divisible by 75 ie.20)
• 11 years agoHelpfull: Yes(1) No(2)
• from 40 we have to minus the numbers which is divisible by 625
• 11 years agoHelpfull: Yes(1) No(1)
• _ _ 25- (1,3,4,6,7)-5P2=20
  _ _ 75- (1,2,3,4,6)-5P2=20
  TOTAL=40
• 11 years agoHelpfull: Yes(1) No(0)
• it is divisible by only 25 but not with 625 and 15625 we observe that the first two places are not 5(4),6 and 25,75 so 3*4=12 again for 75 in last 3*4=12 24
  
• 10 years agoHelpfull: Yes(1) No(0)
• 40...... i slove this question in Elitmus exam
  
• 11 years agoHelpfull: Yes(0) No(13)
• we have 00,25,50,75 as possibilities that if the no. end with these it is div by 25.but 0 is not there so we have 25 and 75 as probability so 5c1*4c1+5c1*4c1=40
• 11 years agoHelpfull: Yes(0) No(3)
• it should not be 40 becoz only once we have to divide . from 40 we have to minus the numbers divisible by 75 and 125
  
• 11 years agoHelpfull: Yes(0) No(0)
• rakesh jee can u plz explain hw the ans is 24
• 11 years agoHelpfull: Yes(0) No(0)
• rakesh please explain your answer
  
• 11 years agoHelpfull: Yes(0) No(0)
• @rakesh
  what about option a and d then?
  
• 11 years agoHelpfull: Yes(0) No(0)