Example 6 - Chapter 7 Class 8 - Proportional Reasoning-1(Ganita Prakash)

Transcript

Example 6 When Neelima was 3 years old, her mother’s age was 10 times her age. What is the ratio of Neelima’s age to her mother’s age? What would be the ratio of their ages when Neelima is 12 years old? Would it remain the same?Given that when Neelima was 3 years old, her mother’s age was 10 times her age. Thus, Mother’s age = 10 × 3 = 30 years Now, Ratio of Neelima’s age to her mother’s age = (𝑁𝑒𝑒𝑙𝑖𝑚𝑎^′ 𝑠 𝑎𝑔𝑒)/(𝐻𝑒𝑟 𝑀𝑜𝑡ℎ𝑒𝑟𝑠 𝑎𝑔𝑒) = 𝟑/𝟑𝟎 = 1/10 = 1 : 10 We need to find Ratio when Neelima is 12 years old Ratio when Neelima is 12 years old We know that when Neelima = 3 years Neelima’s mother = 30 years So, when Neelima = 12 years = 3 + 9 years Neelima’s mother = 30 + 9 = 39 years Now, Ratio of Neelima’s age to her mother’s age = (𝑁𝑒𝑒𝑙𝑖𝑚𝑎^′ 𝑠 𝑎𝑔𝑒)/(𝐻𝑒𝑟 𝑀𝑜𝑡ℎ𝑒𝑟𝑠 𝑎𝑔𝑒) = 𝟏𝟐/𝟑𝟗 = 4/14 = 4 : 13 Thus, ratio changed from 1 : 10 to 4 : 13