How do we calculate p?

What is P(C and Z)?

I need help solving this question please and I also need it in a chart table. The first paper is an example that I took notes in class while the second paper is the question 10 that I need help solving it.

Weight of a rock: In a geology course, students are learning to use a balance scale to accurately weigh rocks. One student plans to weigh a rock 20 times and then calculate the average of the 20 measurements to estimate her rock's true weight. A second student plans to weigh a rock 5 times and calculate the average of the 5 measurements to estimate his rock's true weight. Which student is more likely to come the closest to the true weight of the rock he or she is weighing?  The student who weighed the rock 20 times.  The student who weighed the rock 5 times.  Both averages would be equally close to the true weight.

After an election, of those surveyed, 56 percent voted for the Democrat candidate, 39 percent voted for the Republican candidate, and 5 percent voted for the independent candidate for governor. Respectively, 56 percent, 48 percent, and 64 percent of those surveyed also voted for the first proposition on the ballot. For those surveyed, ______________ percent of them voted for the first proposition on the ballot.  Your answer should be to 4 decimal places.