In how many years will a sum of money doubles itself at 5% per annum simple interest

• 20 years
  
  let the initial sum be 10
  given 5% interest per annum (0.5 in case of 10)
  by these calculations we can summarise it
• 11 years agoHelpfull: Yes(8) No(4)
• let the initial sum be x
  then,Amount=2x(because sum will be double)
  Amount = Principal + S.I
  2x = x + s.I
  S.I = x
  S.I = (p*r*t)/100
  x = (x*5*t)/100
  therefore,t = 20 years
• 11 years agoHelpfull: Yes(8) No(2)
• a simple formula for this type of questions are there
  sum=100(t-1)/r
  t=2,r=5(given)
  sum=100(2-1)/5=20 years
• 11 years agoHelpfull: Yes(7) No(1)
• let time is t then interest = (x*5*t)/100 where x is initial amount
  and initial sum is to be double interest should be equal to x so
  x=(x*5*t)/100
  
  t=20 years
• 11 years agoHelpfull: Yes(4) No(2)