How would you even start to solve this problem
x+10+y+36+t+z+80=420
-10 -36 -80
x+y+t+z=294 (we already know that y+z=90)
-y -z -90
x+t=204 (We already know that t=94)
-t -94
x=110
So now, since 210 people are enrolled in Computers, and we already know three out of the 4 computer slots in the venn diagram circle:
210-110-36-10=z
z=54 (that's your answer for how many students are taking all three courses)
Finally, you can do one of 5 things to figure y out:
1) solve for y in the equation with all of the variables equaling 420
x+10+y+36+z+80=420
x+y+t+z=294
y=294-110-94-54
2) Solve for y soley by using the rest of the fine arts numbers.
Total Fine Arts Students: 180
180-80-10-54=y
3) Do the same thing as above, but for Economics:
Total Eco Students: 220
220-94-54-36=y
4) Use the mini equation that we came up with z+y+t=184
z equals 54, & t=94 so
184-54-94=y
5) Use the OTHER mini equation z+y=90
z=54 so
90-54=y
So,
1. 94/500
2. 36/500
3. 54/500