sharma1617

PERMUTATION AND COMBINATION A teacher prepares a test. She gives 5 objective type question out of which 4 have to be answered. Find the total ways in which they can be answered if the first 2 questions have 3 choice and last 3 have 4 choice. help me with this question,,is there any specific formula applied in thes type of questions???

This question is not from GMAT preparation. This is from cracking the GRE from princeton review. Since i got stuck by this question that why asked it, and yes the correct answer is 16%

The fourth grade at school X is made up of 300 students who have a total weight of 21,600 pounds. If the weight of these four graders has a normal distribution and standard deviation equals 12 pounds, approximately what percentage of the fourth graders weighs more than 84 pounds? a 12% b 16% c 36% d 48% e 60% need detailed explanation,,and also want to know what are bell curve questions and how it will relate with standard deviaion. thanks