Transactions to a computer database are either new items or changes to previous items. the addition of an item can be completed in less than 100 milliseconds 90% of the time, but only 20% of changes to a previous item can be completed in less than this time. if 30% of transactions are changes, what is the probability that a transaction can be completed in less than 100 milliseconds? (question 2-176) (put solution in the form 0.xx)