A student obtained a mean score of 62 in 5 subjects. After the score of a 6\text{th} subje… — JAMB UTME

A student obtained a mean score of $62$ in $5$ subjects. After the score of a $6\text{th}$ subject was added, the overall mean score became $65$ . What is the score obtained in the $6\text{th}$ subject?

Answer: 80

Answer

The score obtained in the 6th subject is 80.

The sum of scores for the first 5 subjects is

5 \times 62 = 310

. With the 6th subject included, the total sum of scores becomes

6 \times 65 = 390

. The score of the 6th subject is the difference between these two totals:

390 - 310 = 80

Step-by-Step Solution

Calculate the total score of the initial 5 subjects

310

The sum of scores for ungrouped data is equal to the number of data items multiplied by the mean: 5 × 62 = 310.

Calculate the total score of all 6 subjects after including the new score

390

The new total score is obtained by multiplying the new count of subjects by the new mean: 6 × 65 = 390.

Determine the score of the 6th subject

The difference between the total score of 6 subjects and the total score of 5 subjects gives the score of the 6th subject: 390 - 310 = 80.

Key Concept

Calculating a missing data value given the mean of ungrouped data before and after addition

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