From past experience a stockbroker believes that under present economic conditions a customer will invest in tax-free bonds with a probability of 0.5, will invest in mutual funds with a probability of 0.5, and will invest in both tax-free bonds and mutual funds with a probability of 0.31. Complete parts (a) and (b) below. (a) At this time, find the probability that a customer will invest in either tax-free bonds or mutual funds. The probability that a customer will invest in either tax-free bonds or mutual funds is. (Type an integer or a decimal. Do not round.) (b) At this time, find the probability that a customer will invest in neither tax-free bonds nor mutual funds. The probability that a customer will invest in neither tax-free bonds nor mutual funds is. Type an integer or a decimal. Do not round.)