We start with the fraction 5
6
. In each move, we can either increase the
numerator by 6 or increases the denominator by 5, but not both. What is the
minimum number of moves to make the value of the fraction equal to 5
6
again?
【Solution】
Since the value of the fraction is unchanged, the ratio of the amount added to the
numerator and the amount added to the denominator is also 5:6. Since we are adding
6s to the numerator and 5s to the denominator, the number of 6s added must be a
multiple of 25 and the number of 5s added must be the same multiple of 36. Hence
the minimum number of moves is 25+36= 61.
ANS: 61