Multiple choice

Amalya invests certain sum at simple interest amounts to rs. 1290 in 3 yrs. and rs. 1410 in 7 yrs. On what principle and at what rate she earned the following amount

  1. 1200rs. , 5%.

  2. 1500rs. , 2.5%

  3. 1200rs. , 2.5%.

  4. 1500rs. , 3 %

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

SI for 4 years (7-3) = 1410 - 1290 = 120. SI for 1 year = 30. SI for 3 years = 90. Principal = 1290 - 90 = 1200. Rate = (SI * 100) / (P * T) = (30 * 100) / (1200 * 1) = 2.5%.

AI explanation

The simple interest for 4 years is the difference between the amounts after 7 years and 3 years, which is 1410 minus 1290 equals 120. The annual interest is 120 divided by 4 equals 30, so the interest for 3 years is 90. The principal is 1290 minus 90 equals 1200. The rate is 100 times interest divided by (principal times time), which is 100 times 90 divided by 3600, equaling 2.5 percent. The principal is 1200rs. and the rate is 2.5%.

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