SOLUTION: In a class of 31 students , 22 study physics , 20 study chemistry & 5 study neither, how many students in the class study both

Question 934868: In a class of 31 students , 22 study physics , 20 study chemistry & 5 study neither, how many students in the class study both
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
In a class of 31 students , 22 study physics , 20 study chemistry & 5 study neither, how many students in the class study both
----------------
Draw a Venn Diagram with 2 intersecting circles labeled physics and chemistry.
----
Let "x" be the number who study both::
Put "x" in the intersection of the 2 circles.
Then 22-x = # who study physics but not chem.
And 20-x = # who study chem and not physics.
Note: 5 are in the rectangle but not in either circle.
---
Equation:
# in circles:: 22-x + 20-x + x = 31-5
42-x = 36
x = 6 (# in the class who study both)
-------------------------
Cheers,
Stan H.
--------------------
RELATED QUESTIONS
In a class of 100 students, it is known that 45 study mathematics, 26 study chemistry and (answered by richwmiller)

n a class of 100 students 55 study Physics, 75 study Chemistry, how many students study... (answered by richwmiller)

In a class of 100 students, it is known that 45 study mathematics, 26 study chemistry and (answered by Theo)

In a year group of 63 students, 22 study biology, 26 study Chemistry and 25 study... (answered by ikleyn)

In a class of 36 students 25 study chemistry and 22 study mathematics and 25 study... (answered by greenestamps,Edwin McCravy,math_helper,AnlytcPhil,ikleyn)

In a school, all of the students study physics or chemistry. Sixty percent of the... (answered by scott8148)

in a class of 30 students, 18 students study history, 16 study geography and 3 study... (answered by ikleyn)

In a class of 80 students, every student studies Economics or Geography or both. If 65... (answered by Jc0110)

Can I have a detailed answer with explanations to the steps for the following question... (answered by greenestamps,ikleyn)