How many positive integers less than 600 can be formed using the numbers 2, 4, 5, and 6 for digits, each digit being used only once.
1)68 2)34 3)52 4)66

• option 2)34
• 4 years agoHelpfull: Yes(6) No(3)
• 34 is right ans.
  1 digit can be use as 4 ways as there are 4 nos = 4
  2 digit _ _ 11 to 99 as 4*3 ways as no repetition is allowed = 4*3 =12
  3 digit 100 to 600 _ _ _ 3*3*2 = 18
  total ways = 18+12+4 = 34
• 4 years agoHelpfull: Yes(3) No(0)
• ans is 1) 68
  we have to get less than 600
  so for 3 digit no less than 600 we get by placing 100th place - 3C1 and at 10th place - 4C1 and at unit place - 4C1
  so for 3 digit we get = 3C1*4C1*4C1 = 3*4*4 = 48
  
  now for 2 digit no at 10th place - 4C1 and at unit place - 4C1
  so we get 2 digit no = 4C1*4C1 = 4*4 = 16
  
  now for 1 digit no we have 4C1 = 4
  
  so total number we get less than 600 are = 48+16+4 = 68
• 4 years agoHelpfull: Yes(1) No(11)
• number should be less than 600 so in 100th place digits can be 2,4,5.
  in 3 numbers we choose 1 , so it would be 3C1=3.
  now 4-1=3 digits are left so, in 10th position it would be 3C1=3
  in unit digit it would be 2C1=2.
  so total possible positive integers =3*3*2=18
• 4 years agoHelpfull: Yes(1) No(3)
• 34 is the answer as it is given that each digit being used only once
• 4 years agoHelpfull: Yes(1) No(0)
• Ant moves smartly so it does not follow the steps ,as along the step's breadth and then height.
  
  If you remember that steps formed right angle,and along the side of wall we found that hypotenuse like length is given,and thus right angle triangle we can say.
  
  Breadth work as base, height as perpendicular and third side is hypotenuse(along the wall)
  
  when base =2 cm and altitude(stairs height) = 1 cm so hypotenuse is √5 ( on applying Pythagoras Theorem)
  
  by the same way hypotenuse of second stair
  I.e. √5 cm
  
  So in total ant walk (√5 +√5) cm to reach the top at point B.
  
  The minimum distance covered by ant to reach from point A to B is 2√5 cm
  
  
  Hope it helps you.
• 4 years agoHelpfull: Yes(0) No(6)