In a class consisting of 75 students, 25 did not know typing, 45 knew shorthand and 10 knew neither typing nor shorthand.
How many students knew both typing and shorthand?
Choose one answer.

a. cannot be determined

b. 25

c. 20

d. 30

• only shorthand + know both shorthand and typing=45--------------eq 1
  only shorthand+neither know typing nor shorthnad= not know typing=25
  only shorthand+10=25
  only shorthand=15
  in eq1
  15+both know shorthand and typing=45
  both know shorthand and typing=30
  so correct answer is c.
• 8 years agoHelpfull: Yes(1) No(0)