Account balance is not proportional to the number of weeks.
12A + 2 + A - 1 = a + 12a + 1 = 13a + 1
X equals 62 because you take 147 and subtract it from 180 and that gives you 33.
then you add 33 and 85 together to give you 118. Then you subtract 118 from 180 and that gives you 62.
x=62
