Multiple choice

Out of a sum of Rs 3,200 a part was spent at 6% simple interest and the other at 9% simple interest. If the interest on the first part after 3 years is equal to the interest on the second part after 6 years, then what is the second part?

  1. Rs 600

  2. Rs 700

  3. Rs 800

  4. Rs 900
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the parts be x and 3200-x. Interest 1 = x * 0.06 * 3 = 0.18x. Interest 2 = (3200-x) * 0.09 * 6 = 0.54(3200-x). Setting 0.18x = 0.54(3200-x) leads to x = 3(3200-x), so x = 9600 - 3x, 4x = 9600, x = 2400. The second part is 3200 - 2400 = 800.

AI explanation

Let the first part be x and the second part be y. Using the simple interest formula, the interest on the first part is (x * 6 * 3) / 100 and the interest on the second part is (y * 9 * 6) / 100. Equating the two yields 18x / 100 = 54y / 100, which simplifies to x = 3y. Since the total sum is Rs 3,200, we have 3y + y = 3200, meaning 4y = 3200. Solving for y gives the second part as Rs 800.

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