Mathematics

Two angles (a + 31) and (b – 49o) are adjacent angles on a straight…

Two angles (a + 31) and (b – 49o) are adjacent angles on a straight line. Which of the following is true
  • A.
    a + b = 198o
  • B.
    a + b = 180o
  • C.
    a + b = 162o
  • D.
    a + b = 100o
  • E.
    a + b = 80o
Correct Answer: Option A
Explanation

a + 31 + b – 49 = 180o(sum of angles on str line)
a + b – 18 = 180o
a + b = 180 + 18
a + b = 198o