- #1
WanderingMind
- 4
- 1
Thread moved from the technical Math forums, so no Homework Help Template is shown
Hello,
I am just looking for some feedback (whether my answers and reasoning is correct) on some practice exercises I am doing. The subject is currently Combinatorics (didn't see a category for that so i just placed this in general math).
Problem 1:
There are 18 mathematics majors and 325 computer science majors at a college.
a) In how many ways can two representatives be picked so that one is a mathematics major and the other is a computer science major?
My answer is 325!/307!
b) In how many ways can one representative be picked who is either a mathematics major or a computer science major?
My answer is 343
Problem 2:
An office building contains 27 floors and has 37 offices on each floor. How many offices are in the building?
My answer is 2737.
Problem 3:
A multiple choice test contains 10 questions. There are four possible answers for each question.
a) In how many ways can a student answer the questions on the test if the student answers every question?
My answer is 410.
b) In how many ways can a student answer the questions on the test if the student can leave answers blank?
My answer is 210 * 410
Problem 4:
A particular brand of shirt comes in 12 colors, has a male and a female version, and comes in three sizes for each sex. How many different types of this shirt are made?
My answer is 72
I am just looking for some feedback (whether my answers and reasoning is correct) on some practice exercises I am doing. The subject is currently Combinatorics (didn't see a category for that so i just placed this in general math).
Problem 1:
There are 18 mathematics majors and 325 computer science majors at a college.
a) In how many ways can two representatives be picked so that one is a mathematics major and the other is a computer science major?
My answer is 325!/307!
b) In how many ways can one representative be picked who is either a mathematics major or a computer science major?
My answer is 343
Problem 2:
An office building contains 27 floors and has 37 offices on each floor. How many offices are in the building?
My answer is 2737.
Problem 3:
A multiple choice test contains 10 questions. There are four possible answers for each question.
a) In how many ways can a student answer the questions on the test if the student answers every question?
My answer is 410.
b) In how many ways can a student answer the questions on the test if the student can leave answers blank?
My answer is 210 * 410
Problem 4:
A particular brand of shirt comes in 12 colors, has a male and a female version, and comes in three sizes for each sex. How many different types of this shirt are made?
My answer is 72