The perimeter of a triangle is 20 cm and the inradius of the triangle is 3 cm. What is the area of the triangle? Choose the correct choice from the following options
A) 22  B) 30  C) 77  D) 54  E) 23

Rationale: "area of a triangle = r * s where r is the inradius and s is the semi perimeter of the triangle . area of triangle = 3 * 20 / 2 = 30 cm 2 answer : b"
Answer: B