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Ramesh and Gautam are among 2222 students who write an examination. Ramesh scores 82.582.5. The average score of the 2121 students other than Gautam is 6262. The average score of all the 2222 students is one more than the average score of the 2121 students other than Ramesh. The score of Gautam is

Solution

✅ Correct Option: 4

Let's break down the information clearly:

22 students total (including Ramesh and Gautam)

Ramesh's score: 82.5

Average of 21 students (excluding Gautam): 62

Key condition: Average of all 22 students = Average of 21 students (excluding Ramesh) + 1

We need to find Gautam's score.


Since the average of 21 students (excluding Gautam) is 62:

Total score of these 21 students = 21 × 62 = 1302

This includes Ramesh's score of 82.5


Here's the crucial insight: We need to use the condition about the averages.

Let's call the average of 21 students (excluding Ramesh) = AA

From the given condition:

Average of all 22 students = A+1A + 1

Now let's express both sides using totals:

Left side: Average of all 22 students = Total of all 22 students22\frac{\text{Total of all 22 students}}{22}

Right side: A+1=Total of 21 students excluding Ramesh21+1A + 1 = \frac{\text{Total of 21 students excluding Ramesh}}{21} + 1


The total score of 21 students (excluding Ramesh) = Total of all 22 students - Ramesh's score

Let Total of all 22 students = TT

So: A=T−82.521A = \frac{T - 82.5}{21}

From our condition: T22=A+1\frac{T}{22} = A + 1

Substituting AA: T22=T−82.521+1\frac{T}{22} = \frac{T - 82.5}{21} + 1


T22=T−82.521+1\frac{T}{22} = \frac{T - 82.5}{21} + 1

Multiply everything by 22×21=46222 \times 21 = 462 to clear fractions:

21T=22(T−82.5)+22×2121T = 22(T - 82.5) + 22 \times 21

21T=22T−22×82.5+46221T = 22T - 22 \times 82.5 + 462

21T=22T−1815+46221T = 22T - 1815 + 462

21T=22T−135321T = 22T - 1353

T=1353T = 1353


From earlier we know:

Total score of 21 students (excluding Gautam) = 1302

Total score of all 22 students = 1353

Therefore: Gautam's score = 1353 - 1302 = 51

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