Of the 60 students of the IT class of 2003 at UC Berkeley, 30 use a Ma

tito411990 , I drew a Venn diagram and got 11 as well.

The formula is a little different when we aren't using "exactly" or "only" two groups.
We need
\(A + B + C -(Both) + (all3) + Neither = Total\)

M = 30
SP = 20
SG = 20
M + SP = 13
M + SG = 5
SP + SG = 8
All 3 = 5

Total of "BOTH"
M + SP = 13
M + SG = 5
SP + SG = 8
(13+5+8) = 26

\(A + B + C -(Both) + (all3) + Neither = Total\)
Thus:
\(30+20+20-26+5+Neither= Total\)
\(75 - 26 + Neither = 60\)
\(49 + Neither = 60\)
\(Neither = 11\)

Answer D

Bunuel explains the formulas masterfully here, In Advanced Overlapping Sets

Hope that helps.

EDIT
tito411990 , you are welcome.
Also, welcome to GMAT club!
Adding a Venn diagram.
1) Most restrictive first. All three = 5 (pink)

2) M and SP, SP and SG, M and SG are represented by
the three gray areas. In each area, use (BOTH - all three)
Mac + SP = 13: 5 from the all 3 group (pink) and 8 who use just 2 of the 3 (gray)

3) Light purple areas, M only, SP only, and SG only, use
For each: TOTAL - (gray + gray + pink)

4) Add all the numbers from inside the circle = total students who used
machines in defined categories
5) All students = 60. Students who use these machines = 49
6) None/Neither = (60 - 49) = 11