Multiple choice

The population of towns A and B is the ratio of 1 : 4. For the next 2 years, the population of A would increase and that of B would decrease by the same percentage every year. After 2 years, their population became equal. What is the percentage change in the population? शहरों A और B की जनसंख्या का अनुपात 1:4 है। अगले 2 वर्षों में, A की जनसंख्या में वृद्धि होगी और B की जनसंख्या में प्रत्येक वर्ष समान प्रतिशत की कमी आएगी। 2 साल बाद उनकी आबादी बराबर हो गई। जनसंख्या में प्रतिशत परिवर्तन कितना है?

  1. 33.33%

  2. 66.66%

  3. 25%

  4. 20%

  5. 21 %
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let population ratio be A:B=1:4, so A=x, B=4x. After 2 years with percentage change p: A(1+p/100)²=B(1-p/100)². This gives x(1+p/100)²=4x(1-p/100)². Taking square roots: 1+p/100=2(1-p/100). Solving: 1+p/100=2-2p/100, so 3p/100=1, p=100/3=33.33%.

Keep practicing — related questions