There are 800 members at a gym.
320 members are over the age of 40, the rest are aged 40 or under.
18\displaystyle \frac{1}{8}81 of the members over 40 use the swimming pool.
16\displaystyle \frac{1}{6}61 of the members aged 40 or under use the swimming pool.
Work out the total number of members who use the swimming pool.
