10 years ago Neha's mother was 4 times older than Neha. After 10 years Neha's mother will be twice Neha's age. How old is Neha now?
Choose the correct choice from the following answers:
A) 10 years	B) 15 years	C) 17 years	D) 20 years	E) 23 years
Let us assume m = mother and n = neha   m-10 = 4(n-10) =&gt; 4n-m = 30 this is equation 1   m+10 = 2(n+10 =&gt; -2n+m = 10 this is equation 2   By equations 1 and 2   n=20   n means Neha age = 20 years   ANSWER:20 years
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10 years ago Neha's mother was 4 times older than Neha. After 10 years Neha's mother will be twice Neha's age. How old is Neha now?