The four interior angles of a quadrilateral are (x + 20) o, (x+ 10) o...

The four interior angles of a quadrilateral are (x + 20) ^o, (x+ 10) ^o (2x – 45) ^o and (x – 25) ^o. Find the value of x

The correct answer is: B

Sum of interior angles in a quadrilateral is 360
(x + 20)^o + (x+ 10)^o + (2x - 45)^o + (x - 25)^o = 360^o
5x^o - 40^o = 360^o
x = 400/5 = 80^o