In an examination there are 100 questions divided into 3 parts A, B and C and each part should contain atleast one question. Each question in parts A, B and C carry 1, 2 and 3 marks respectively. Part A is for atleast 60% of the total marks and part B should contain 23 questions. How many questions must be set in part C?
Explanation
Step 1: Formulate the basic equations
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Total number of questions:
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Given that Part B contains 23 questions:
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Substituting y into the total:
Step 2: Determine Total Marks
The marks for each part are:
Substitute x=77−z into the total marks equation:
Step 3: Apply the condition for Part A
Part A must be at least 60% of the total marks:
Now, solve for z:
Step 4: Final Constraint
Since z represents the number of questions, it must be a positive integer. The problem states each part contains atleast one question, so z≥1.
Based on our inequality z≤1.45, the only possible integer value for z is:
Conclusion:
There must be 1 question in part C.
Correct Option: (a) 1
Explanation
Step 1: Formulate the basic equations
-
Total number of questions:
-
Given that Part B contains 23 questions:
-
Substituting y into the total:
Step 2: Determine Total Marks
The marks for each part are:
Substitute x=77−z into the total marks equation:
Step 3: Apply the condition for Part A
Part A must be at least 60% of the total marks:
Now, solve for z:
Step 4: Final Constraint
Since z represents the number of questions, it must be a positive integer. The problem states each part contains atleast one question, so z≥1.
Based on our inequality z≤1.45, the only possible integer value for z is:
Conclusion:
There must be 1 question in part C.
Correct Option: (a) 1