On a primary school parents were asked the number of hours they spend to help their children in home work there were 90 parents who helped 1/2 hour to 1 1/2 hours . 20% of parents helped more than 1 1/2 hours 30% said that they helped for 1/2 hour to 1 1/2 hours per day the rest 50% did not help at all
(i)how many parents were surveyed
(ii)how many said they did not help