In a primary school parents asked about of the number of hours they spend per day in helping their children to do home work.

There were 90 parents who helped for `frac(1)(2)` hour to `1frac(1)(2)` hours. The distribution of parents according to the time for which, they said they helped is given in the adjoining figure, 20% helped for the than `1frac(1)(2)` hours per day, 30% helped for `frac(1)(2)` hour to 1 hours, 50% did not help at all. Using this, answer the following :
How many said that they helped more than `1frac(1)(2)` hours?