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Anu is two years older than Kanu, who is twice as old as Tanu. If the total of their ages is 32, then what is the difference in age of Anu and Tanu?
14 years
8 years
7 years
12 years
8 years
Express all ages in terms of one variable: T=x, then K=2x and A=2x+2. The sum is 5x+2=32, giving 5x=30, so x=6.
Age of Anu = (Age of Kanu) + 2, Age of Kanu = 2 * (Age of Tanu), Sum of ages = 32.
A=K+2, K=2T, A+K+T=32
Express all ages in terms of one variable: T=x, then K=2x and A=2x+2. The sum is 5x+2=32, giving 5x=30, so x=6.
Students often calculate the age of Anu or Kanu and mark it as the answer, forgetting that the question specifically asks for the difference between the ages of Anu and Tanu.
Define variables and relationships
Let the age of Tanu be T. Given that Kanu is twice as old as Tanu, we have K=2T. Since Anu is two years older than Kanu, we have A=2T+2.
A=2T+2,K=2T
Set up the sum equation
The sum of their ages is given as 32. Substituting the expressions in terms of T gives (2T+2)+2T+T=32.
5T+2=32
Solve for Tanu's age
Solving 5T=30 results in T=6. So, Tanu is 6 years old.
T=6
Calculate Anu's age and the final difference
Using T=6, we find A=2(6)+2=14. The difference between the ages of Anu (14) and Tanu (6) is 14тИТ6=8.
AтИТT=14тИТ6=8
B is correct because the calculated age difference between Anu and Tanu is 8 years.
This type of algebra problem is common in exams; always represent all quantities in terms of the smallest variable to simplify the addition.