For aiming at a target a person gets one rupee each time when he hits it and loses one rupee when he misses it. If he gets ₹ 30 after aiming at the target one hundred times, then how many times did he miss the target?
Aptitude
Simplification
Difficulty: Easy
Choose an option
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A25
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B35
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C40
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D45
Answer
Correct Answer: 35
Explanation
### Concept & Strategy
This is an algebraic word problem mapping actions to gains and losses. Since the gain and penalty are identical (₹ 1), the problem reduces to a simple system of linear equations involving sum and difference.
$$ \text{Hits} + \text{Misses} = \text{Total Attempts} $$
$$ \text{Hits} - \text{Misses} = \text{Net Score} $$
### Step-by-Step Solution
* **Given:** Total aims (attempts) = 100. Gain per hit = +1. Loss per miss = -1. Final amount = ₹ 30.
* **Set up equations:** Let $h$ be hits and $m$ be misses.
1. $h + m = 100$ (Total attempts)
2. $1h - 1m = 30$ (Net financial result)
* **Solve the system:** Add Equation 1 and Equation 2 together.
* $(h + m) + (h - m) = 100 + 30$
* $2h = 130$
* $h = 65$ (Total hits)
* **Calculate misses:** Substitute $h$ back into the first equation.
* $65 + m = 100$
* $m = 100 - 65 = 35$
### Exam Strategy & Shortcut
Using the "Assumed Total" shortcut: If he hit all 100 times, he would have ₹ 100. He actually has ₹ 30. The difference is ₹ 70. Every miss costs him ₹ 2 (the ₹ 1 he didn't win + the ₹ 1 penalty he pays). Total misses = $\frac{70}{2} = 35$. This mental math takes less than 5 seconds.
### Common Pitfall
Solving perfectly for $h$ (Hits = 65) but forgetting what the question actually asked for. The question asks for the number of *misses*, not hits. Always re-read the final sentence of the question before marking your option.
### Final Answer
**Therefore, the correct answer is 35.**