The following question has three statements. Study the question and the statements and decide which of the statement (s) is/are necessary to answer the question. What is the current age of Sonam? I) When Shreya was 10 years old, Sonam’s age was half than Shreya’s age II) Four years ago, Preeti’s age was three times than Sonam’s age III) At present, Preeti’s age is double than Shreya’s age
The following question has three statements. Study the question and the statements and decide which of the statement (s) is/are necessary to answer the question. What is the current age of Sonam? I) When Shreya was 10 years old, Sonam’s age was half than Shreya’s age II) Four years ago, Preeti’s age was three times than Sonam’s age III) At present, Preeti’s age is double than Shreya’s age Correct Answer All statements are required
Considering Statement I,
When Shreya was 10 years old, Sonam’s age was half than Shreya’s age
It means that Sonam is 5 years younger than Shreya
Hence, this statement is not enough to get the answer
Considering Statement III,
At present, Preeti’s age is double than Shreya’s age
Let the current age of Shreya be x years
Then, the current age of Preeti will be 2x years
But, this statement alone is not enough to get the answer
Considering Statement II,
Four years ago, Preeti’s age was three times than Sonam’s age
Current age of Preeti is 2x years
Then, four years ago her age was 2x - 4 years
Four years ago Sonam’s age will be (2x - 4)/3 years
This statement alone is also not enough to get the answer
Considering I, II and III together,
From II, the current age of Shreya is x years
From III, four years ago Sonam’s age was (2x - 4)/3 years --- (1)
Four years ago Shreya age will be x - 4 years
From I, Four years ago Sonam’s age will be = x - 4 - 5 years = x - 9 years --- (2)
From (1) and (2),
(2x - 4)/3 = x - 9
⇒ 2x - 4 = 3x - 27
⇒ 27 - 4 = 3x - 2x
⇒ x = 23
Current age of Shreya is 23 years
∴ So, current age of Sonam is 23 - 5 i.e. 18 years