Given average age of three friends is 20 years Sum of their ages =3×20=60 years Given, their ages are in ratio 2:3:5. Let their ages be 2x,3x and 5x 2x+3x+5x=60 10x=60 x=6 Their ages are 12 years, 18 years and 30 years Age of oldest friend =30 years Answer is option C.