Posted by stacey on Thursday, November 10, 2011 at 6:57pm.
in a class of 30 students, 17 have computers at home and 20 have cassettes. If 4 students in the class have neither a computer or a cassette, how many of the 30 students have both?

math  Steve, Thursday, November 10, 2011 at 7:24pm
If you count all the students with computers, and then count all those with cassettes, you count twice the ones that have both. So, adjust the total accordingly.
30 students. 4 with nothing, leaves 26 with either computer or cassette or both
17+20 = 37, but there are only 26 students available, so there must be 3726=11 with both. Just adding up the numbers counted 11 of them twice.
Answer This Question
Related Questions
 Math  In Mrs Halls class of 30 students, 17 have computers at home and 20 have ...
 Statistics  Suppose 52 of the students in class have a calculator and 14 have a...
 Venn Diagrams  In a class of 50 students, 36 students have a sandwich in their ...
 statistics  in a class of 100,84% of student have taken politics and 16% of the...
 math  48.Kate's class has between 40 and 51 students. Exactly of 75%of the ...
 statistics  In a class of 100 ,84% of the students have taken politics &16% of ...
 math  There are x students in Mrs. Schwartz's thirdgrade class. One less than ...
 math (check answer)  You want to know the number of students in your school ...
 Math  Of the 597 students at Duzine Elementary School, 19% have a computer at ...
 Math  Ms. Tenley's class has 25 students. Two of the students have visited no ...
More Related Questions