A runner completes the first 10 laps of a 15-lap race at an average speed of 1 minute and thirty seconds per lap. How fast will the runner’s average lap time need to be for the last five laps if they want to have average per-lap speed of one minute and twenty-five seconds for the entire race?

If you could answer these your a life saver

Using pert, adam munson was able to determine that the expected project completion time for the construction of a pleasure yacht is 21 months, and the project variance is 4. a) what is the probability that the project will be completed in 17 months? b) what is the probability that the project will be completed in 20 months? c) what is the probability that the project will be completed in 23 months? d) what is the probability that the project will be completed in 25 months? e) what is the due date that yields a 95% chance of completion?

Can someone me and explain..will award brainlest!