In a class of 30 students, 4x use cellular phone, x use both cellular and mobile phones, 20 use mobile phones and 2 use neither mobile nor cellular phones, What is the value of x?
x students uses mobile and cellular phones,
4x-x uses cellular phones,
20-x students use mobiles,
2 students don,t use any thing
now we put the given values in equation,4x-x+x+20-x+2=30
=> 3x+22=30
= 3x=30-22
=3x=8
=x=8/3