Given: Arun's present age + 7 years = Bidan's present age - 4 years Charan's present age = 2 years Arun, Bidan and Charan average age after 10 years = 33 years Formula used: Average = Sum of observation/Total number or observation Calculation: The present average age of Arun, Bidan and Charan = 33 - 10 = 23 years Relation between Arun's age(A) and Bidan's age (B) is A + 7 = B - 4 ⇒ A - B = - 11 years ----(i) Present age total 23 × 3 = 69 years A + B + 2 = 69 ⇒ A + B = 67 ----(ii) Aftere solving equation (i) and (ii) 2A = 67 - 11 ⇒ A = 56/2 = 28 years ∴ The present age of Arun is 28 years