Mode of grouped data by the formula

This type of question, asked 3 times: CDS 1 2023, CDS 2 2024, CDS 2 2026. All 3 questions below, oldest first.

Try each one first, then open its answer.

Question 1 (case study, 2 parts)
CDS 1 2023
Consider the following data for the next two (02) items that follow :
Class 0 - 30 30 - 60 60 - 90 90 - 120
Frequency 4 5 7 4
81 $What is the mode of the distribution ?$
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82 $7(Q - P) = 9R$
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Question 2 (case study, 2 parts)
CDS 2 2024
A frequency distribution is as follows :
Marks 18-26 27-35 36-44 45-53 54-62 63-71 72-80
Number of students 5 7 10 15 8 3 2
54 $What is the median of the distribution ?$
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55 $What is the mode of the distribution ?$
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Question 3
CDS 2 2026
96 $Consider the following grouped data : Class Frequency 0 - 10 4 10 - 20 8 20 - 30 15 30 - 40 10 40 - 50 3 What is the mode of the above distribution ?$
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Question 1 (case study, 2 parts)