On Mars a day is called a sol. Mars has a 668-sol year with a 7-sol week. If a regular Martian year has 95 weeks, and a leap year is one week longer, what fraction of the years are leap years? Express your answer as a common fraction.
668/7 = 95.4285714285714286 Number of weeks in a Sol-year
the decimal portion will be part of the sol week
0.4285714285714286 x 7 = 3.0000000000000002 days
every 7 years would be 21 days or 3 weeks
so in 7 years they would need 3 Leap Years