what is the unit digit in 27^20

• unit digit of 27 is 7 having power 20 which means 4n..
  7^20=1
• 10 years agoHelpfull: Yes(25) No(2)
• 1
  27^20=27^(2*10)
  =27^(2*2*5 )
  for unit place (7^4)^5
  =1^5=1
• 10 years agoHelpfull: Yes(17) No(2)
• TO FIND UNIT DIGIT WE HAVE TO FOLLOW 3 RULES ....
  
  LAST DIGIT =ANYONE OF THESE ( 0,2,3,7,8) GOES TO CYCLIC RULE DIVIDE ( POWER NO BY 4) & FIND REMDR. IF REMD =0 THEN PUT 4
  = 1 THEN PUT 1
  =2 THEN PUT 2
  =3 THEN PUT 3
  
  RULE ii - IF LAST DIGIT EITHER 4 OR 9 GOES TO
  IF POWER EVEN ADD +2 = 4+2 =6 LIKE .124^20005554 =6
  =9+2=11 LIKE 589^4500008= 1
  OTHERWISE WRITE SAME
  (254)^8555541 =4
  ( 366666666666888879)^45555555588888888893 =1
  
  AND LAST RULE IF LAST DIGIT ONE OF (1,5,6)
  UNIT DIGIT SAME I.E
  (122201)^525544 =1
  5555555^69887=5
  4256986^653=6
  
  
  NOW GOES TO THIS QWESTION - (27)^20 ie. last digit =7 goes to cyclic rule = 20/4 ,remd =0 thus write 4
  7^4 = 1 anssssss
  
  
  
  
  
  
• 9 years agoHelpfull: Yes(9) No(0)
• use cyclicity rule... that all
• 9 years agoHelpfull: Yes(4) No(0)
• When the given number is odd then try to get the last digit as 1.
  27^4*5
  7^4=1
• 9 years agoHelpfull: Yes(3) No(0)
• (7) ^ 4*5 ans 1
  
• 9 years agoHelpfull: Yes(3) No(0)
• In unit place is 7 => 7^2=49
  Unit place is 9 => 9*7= 63
  Unit place is 3 => 3*7=21
  There fore Units place of 27^4=1
  there fore units place is 7^20=>7^4^(5)=1^5=>1
• 10 years agoHelpfull: Yes(2) No(1)
• First We know the power cycle of 7 then we can solve answer fast
  i.e. divide the power by power cycle i.e. 20/4 4 is power cycle of 7 unit place then
  20/4=Reminder is 0 then take the hightest power of power cycle i.e. 4 then 7^4=2401 then
  unit place is =1 is the correct ans.
  
  
• 10 years agoHelpfull: Yes(2) No(1)
• Cyclicity of 7 is 4.
  20/4 gives remainder 0.
  So the unit digit should be 7(i.e the unit digit of 27)^0=1
  :-)
• 9 years agoHelpfull: Yes(2) No(0)
• ans is 1
  unit digits :7^1..............7
  7^2.............9
  7^3............3
  
  
  
  
  
  
• 10 years agoHelpfull: Yes(1) No(0)
• Ans-:1
  27^20=(3^3)^20=3^60
  unit digits of 3^N repeat as =3,9,7,1...(since 3^1=3, 3^2=9, 3^3=27, 3^4=81,3^5=243....)
  so, 3^60 has unit digit 1
  
• 9 years agoHelpfull: Yes(1) No(0)
• 
  
  27^20
  7 ^0 = 1
  
  so 1
• 9 years agoHelpfull: Yes(1) No(0)
• if the unit digit is 2,3,7,8 divide the power with 4
  in the above questn in units place 7 ,so divide the 20 with 4
  we vil get the reminder as 0 whenevr dividing vit 4 if we get remainder as 0 we need to take last value in 4th table ie the ans is 6 (
  4^1=4
  4^2=6
  4^3=4 repeating no need to consider)
• 10 years agoHelpfull: Yes(0) No(3)
• 27^20
  20/4 gives 0 as remainder.
  therefore at unit place 7^4 gives= 7*7=49
  now, 9*7=72
  now, 2*7=14, therefore unit place is 4.
• 10 years agoHelpfull: Yes(0) No(4)
• 20/4 we get remainder 0 then consider as 4
  7^4=81
  ans unit digit is 1
• 9 years agoHelpfull: Yes(0) No(0)
• Cyclicity of 7 is 4.
  then 7^4=2401.
  unit digit is 1.
• 9 years agoHelpfull: Yes(0) No(0)
• divide the base with 10 and power with 4 ,because to get units digit e divide it with 10,,,nd cyclicit of any number z 4.. i.e after every four times the unit digits are same...
  cyclicit of 7 is 7,9,3,1.when we divide power with 4 the remainder is 0.i.e 4... so ans is 1
• 9 years agoHelpfull: Yes(0) No(0)
• Guys...go thru Arun Sharma (Quant ) for this type of problems ..... easy, helpful and time efficient methods are there....
• 9 years agoHelpfull: Yes(0) No(0)
• 27^20
  20(mod 4) =0
  27^20 unit digit 1
• 9 years agoHelpfull: Yes(0) No(0)
• the unit digit=1
• 9 years agoHelpfull: Yes(0) No(0)
• ans will be 1
  becoz
  if we use cyclic rule here we will get 7^4 which results in 1 at unit place
• 8 years agoHelpfull: Yes(0) No(0)
• 27^20
  To get the unit digit we only look at unit digit power
  
  27^20
  =7^20
  =9^10
  =1^5
  =1
• 5 years agoHelpfull: Yes(0) No(0)