In a group of 100 people, 60 have a DVD player, 50 have a CD player, and 30 have neither. How many people have both?

In a large family, 20 have parrots, 15 have rabbits, and 5 have both. One own a pet dog. How many family members own only a pet rabbit?

Of the 137 students who took a mathematics exam, 57 correctly answered the first question, 65 correctly answered the second question, and 23 correctly answered both questions. How many students did not answer either of the two questions correctly? students did not answer either of the two questions correctly.

Radio stations that are on the eastside of a nation have call letters consisting of a W followed by four letters (W can be used​ again). How many different call letters of this type are​ possible?

A class has 13 ​students, of which 4 are seniors. How many committees of size 4 can be selected if at least one member of each committee must be a​ senior?       The number of committees is

The newest cars have 12 different accessories and the buyer pays for each one separately.  If a particular buyer wants to buy four accessories, how many different accessory packages will there be?

There are 100 students who are taking history or sociology. If 10 are taking both courses and 45 are taking just history, how many are taking sociology?

Suppose you have a choice of ten TV sets that can be matched with any of six DVR players and eight DVD players. How many different TV/DVR/DVD systems can you assemble?

A company owns buses that hold only 25 people. How many of these buses are required to transport 107 people?

A cell phone company offers 19 different voice packages and 19 different data packages. Of those, 6 packages include both voice and data. How many ways are there to choose either voice or data, but not both?