What z-score separates the highest 60% from the rest of the scores?

For a normal distribution,a. What z-score separates the highest 25% from the rest of the scores?b. What z-score separates the highest 60% from the rest of the scores?c. What z-score separates the lowest 30% from the rest of the scores?d. What z-score separates the lowest 80% from the rest of the scores?