Question 6 - Figure it out - Page 176, 177 - Chapter 7 Class 8 - Proportional Reasoning-1(Ganita Prakash)

Transcript

Question 6 Harmain is a 1-year-old girl. Her elder brother is 5 years old. What will be Harmain’s age when the ratio of her age to her brother’s age is 1 : 2?Now, Harmain’s age = 1 year Harmain’s brothers age = 5 years Thus, we can say that Harmain’s brother age = Harmain’s age + 4 years We have to find Harmain’s age when the ratio of her age to her brother’s age is 1 : 2 Here, ratio 1 : 2 means Thus, we can say that Harmain’s age : Harmain’s brother age = 1 : 2 Converting into fraction (𝐻𝑎𝑟𝑚𝑎𝑖𝑛^′ 𝑠 𝑎𝑔𝑒)/(𝐻𝑎𝑟𝑚𝑎𝑖𝑛^′ 𝑠 𝑏𝑟𝑜𝑡ℎ𝑒𝑟 𝑎𝑔𝑒)=1/2 2 × Harmain’s age = Harmain’s brothers age Harmain’s brothers age = 2 × Harmain’s age Now, putting this equation into our earlier equation Harmain’s brother age = Harmain’s age + 4 Putting Harmain’s brothers age = 2 × Harmain’s age 2 × Harmain’s age = Harmain’s age + 4 2 × Harmain’s age – Harmain’s age = 4 Harmain’s age × (2 – 1) = 4 Harmain’s age = 4 years Thus, Harmain’s brothers age = 2 × Harmain’s age = 2 × 4 = 8 years Thus, Harmain will be 𝟒 years old.