Multiple choice

The value of 8% of a gadget's selling price equals 10% of its cost price. Furthermore, 15% of the selling price exceeds 18% of the cost price by Rs. 90. Determine the ratio of the cost price to the selling price.

  1. 3 : 5

  2. 3 : 4

  3. 5 : 4

  4. 4 : 5

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

0.08S = 0.10C => S/C = 10/8 = 5/4. 0.15S - 0.18C = 90. Substitute S = 1.25C: 0.15(1.25C) - 0.18C = 90 => 0.1875C - 0.18C = 90 => 0.0075C = 90 => C = 12000. S = 15000. Ratio C:S = 12000:15000 = 4:5.

AI explanation

From the first condition, 0.08S equals 0.10C, which simplifies to the ratio C:S as 4:5. Verifying with the second condition, 0.15S minus 0.18C becomes 0.15(5x) minus 0.18(4x), equaling 0.75x minus 0.72x, which is 0.03x; setting this to 90 means x equals 3000. This satisfies the conditions and confirms the ratio is 4:5.

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