Questions : In an exam one student get 25% marks and falls by 30 marks. Another student get 40% which is 60 more than the passing mark. Find the passing percentage?
Answer:
Shortcut Rule for Passing Marks Calculation
We can use the formula:
Applying the Formula
Given:
- First student scored 25% and failed by 30 marks.
- Second student scored 40%, which is 60 marks more than passing marks.
- Difference in percentage = 40% - 25% = 15%.
- Total difference in marks = 30 + 60 = 90.
Now, using the formula:
Finding Passing Percentage
Thus, the passing percentage is 30%, calculated quickly using the shortcut!
Additional Techniques
Here's how to solve this problem:
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Set up variables:
- Let 'P' be the passing marks.
- Let 'T' be the total marks.
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Create equations based on the given information:
- Student 1: 0.25T = P - 30 (25% of total marks is 30 less than passing marks)
- Student 2: 0.40T = P + 60 (40% of total marks is 60 more than passing marks)
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Solve the system of equations: We can solve for 'T' and 'P' using substitution or elimination. Here's one way using elimination:
Subtract the first equation from the second equation:
(0.40T - 0.25T) = (P + 60) - (P - 30)
0.15T = 90
T = 90 / 0.15
T = 600
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Substitute T back into one of the equations to find P: Let's use the first equation:
0.25 * 600 = P - 30
150 = P - 30
P = 150 + 30
P = 180
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Calculate the passing percentage:
Passing percentage = (P / T) * 100
Passing percentage = (180 / 600) * 100
Passing percentage = 30%
Answer: The passing percentage is 30%.