Multiple choice

Any amount becomes 500 in 4 years at the rate of compound interest and becomes 800 in 8 years then what is the principal? कोई राशि चक्रवृद्धि ब्याज की दर से चार वर्षों में 500 रू. तथा 8 वर्षों में 800 रू. हो जाए तो वह राशि क्या है?

  1. 212.50

  2. 312.50

  3. 325.50

  4. 333
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Amount becomes 500 in 4 years and 800 in 8 years. Let P = principal. P(1+r)⁴ = 500, P(1+r)⁸ = 800. Dividing: (1+r)⁴ = 800/500 = 8/5. So P(8/5) = 500, P = 500 × 5/8 = 312.50. Verification: 312.50(8/5) = 500, and 500(8/5) = 800. Other options don't work.

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