What is the smallest number ,which when divided by 7,18,56 and 36, leaves a remainder 0?
a, 390
b, 392
c, 504
d, 1012

• c)504
  take l.c.m of 7,18,36 and 56 gives 504
• 10 years agoHelpfull: Yes(14) No(5)
• answer is c ,smart technique is to pick a no like i did.. i choose 36 and try to divide the no. 504 is d only no. which leaves remainder 0.
  
• 10 years agoHelpfull: Yes(2) No(1)
• leaves a remainder zero = completly divisible
  so the smallest number, which is completly divisible by 7, 18, 56 and 36 = LCM ( 7 , 18 , 56 , 36 ) = 504
• 8 years agoHelpfull: Yes(2) No(0)
• lcm (7,18,56,36)=504 so ans is c
• 10 years agoHelpfull: Yes(1) No(0)
• 504 is the answer
• 10 years agoHelpfull: Yes(1) No(0)
• 504 is the answer.check the options one by one
• 10 years agoHelpfull: Yes(0) No(0)
• LCM OF 7,18,56,36 is 504
  so Ans is 504
• 9 years agoHelpfull: Yes(0) No(0)
• 7,18(2*9),56(7*8),36(18(2*9)*2)........so each num is divided by 2,7,8,9
  
• 9 years agoHelpfull: Yes(0) No(0)
• 504
  which is divisible by 7,18,56,36
• 8 years agoHelpfull: Yes(0) No(0)
• 7 is a factor of 56 and 18 is a factor of 36.
  so if we check for these two possibilities, we get the answer.
  56*9=504
  36*14=504
• 8 years agoHelpfull: Yes(0) No(0)
• To find the answer to these type of question we use LCM - which is the least common multiple.
  
  This will give the minutes after which the mark will be aligned again. 
  
  Hence we are going to find the least common multiple of 36, 24, 60
  
  36 = 36,72,108,144,180,216,252,288,324,360
  
  24 = 24,48,72,96,120,144,168,192,216,240,264,288,312,336,360
  
  60 = 60,120,180,240,300,360
  
  We can see that the least common multiple of the 36,24 and 60 = 360
  
  Therefore the marks will be aligned again after 360 minutes = 360/60 hours
  
  = After 6 hours.
• 6 years agoHelpfull: Yes(0) No(0)
• 18=2*9;
  all no divisible by 2
  3+9+0=12 not divisible by 9
  3+2+9=14 not divisible by 9
  5+0+4=9 divisible by 9
  1+0+1+2=4 not divisible by 9
  so answer is c i.e 504 no need to take lcm
• 4 years agoHelpfull: Yes(0) No(0)
• but lcm gives ans as 1008
• 4 years agoHelpfull: Yes(0) No(0)
• LCM OF 7,18,56,36=504
• 4 years agoHelpfull: Yes(0) No(0)