Q2 of 157 Page 38

Frame and solve the equations for the following statements:

Mary is 3 times older than Nandhini. After 10 years the sum of their ages will be 80. Find their present ages.

At present,


Let age of Nandini = x


Then age of Mary = 3x


After 10 years,


Age of Nandini = x + 10


Age of Mary = 3x + 10


Then according to the question,


[x + 10] + [3x + 10] = 80


⇒ x + 10 + 3x + 10 = 80


⇒ 4x + 20 = 80


⇒ 4x = 80 – 20


⇒ 4x = 60


⇒ x = 15


⇒ 3x = 3 × 15 = 45


Hence, Present age of Nandini = 15 years


Present age of Mary = 45 years


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