Help. It's about sets.

"A survey is conducted with 39 students, as to what activties they did over the Christmas holidays. It was found that: 15 had family dinners, 18 went to party, x did both and 3x did neither.
i. Calculate the value of x.
ii. Illustrate in Venn diagram

Question

Help. It's about sets.

"A survey is conducted with 39 students, as to what activties they did over the Christmas holidays. It was found that: 15 had family dinners, 18 went to party, x did both and 3x did neither.
i. Calculate the value of x.
ii. Illustrate in Venn diagram

anonymous · Answer

|dw:1371568457725:dw|
$$39=(18+15-X)+3X$$
Solve and get the value of x.

anonymous · Answer

thank you. I'll do it now.

anonymous · Answer

here A=18
B=15
$$A and B=x,     \not A and B =3x$$

anonymous · Answer

X=3....thank you so much!:)