The price of groundnuts increased by x%per week over 2 successive weeks. If at…
2026
The price of groundnuts increased by x%per week over 2 successive weeks. If at the beginning, 2 Kgs were available for Rs 80 and after 2 weeks they were available for Rs 105.80, what is the value of x?
- A.
10%
- B.
12%
- C.
15%
- D.
20%
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Show answer & explanation
Correct answer: C
Key idea: use compound growth: final = initial × (1 + x/100)².
Compute the growth factor: 105.80 ÷ 80 = 1.3225.
Find the weekly factor by taking the square root: √1.3225 = 1.15.
So 1 + x/100 = 1.15 ⇒ x/100 = 0.15 ⇒ x = 15%.
Check: 80 × 1.15² = 80 × 1.3225 = 105.80, which matches the given final price.