A binary operation (oplus) defined on the set of real number is such that x(oplus)y = xy/6 for all x, y ∈ R. Find the inverse of 20 under this operation when the identity element is 6
- A.^{1}/_{12}
- B.^{10}/_{3}
- C.^{1}/_{20}
- D.^{9}/_{5}
Correct Answer: Option D
Explanation
x ⊕ y = xy/6 = xe/6 = x
xe = 6x
e = 6
x ⊕ y = xx1/6 where x1 = 20
x x 20/6 = 6
x = 36/20
x = 9/5