Question 15 - MCQs from NCERT Exemplar - Chapter 3 Class 10 Pair of Linear Equations in Two Variables

Transcript

Question 15 The father’s age is six times his son’s age. Four years hence, the age of the father will be four times his son’s age. The present ages, in years, of the son and the father are, respectively: 4 and 24 (b) 5 and 30 (c) 6 and 36 (d) 3 and 24 Let the Present Age of Son = x years Present Age of Father = y years Given that Father’s age is 6 times son’s age y = 6x Four years later, Age of the father will be four times his son’s age Age of father after 4 years = 4 × Age of son after 4 years y + 4 = 4 × (x + 4) y + 4 = 4x + 16 y = 4x + 16 − 4 y = 4x + 12 Putting y = 6x from (1) 6x = 4x + 12 6x − 4x = 12 2x = 12 x = 12/2 x = 6 Putting x = 6 in (1) y = 6x y = 6 × 6 y = 36 Thus, x = 6, y = 36 So, the correct answer is (C)