Let p represent # of physics texts sold
Let m represent # of maths texts sold
Therefore we have p = m - 60 | because physics texts sold are less than maths by 60
Total sold = 206 = m + p | recall that p = m - 60
We then have 206 = m + m - 60
206 = 2m - 60 | adding 60 to both sides, we have
206 + 60 = 2m | dividing both sides by 2
266/2 = 2m/2
Therefore, m = 133 texts
and p = m - 60 = 133 - 60 = 193
