Economy, asked by urvashisannu031, 1 year ago

the average marks of 39 students of a class are 50 the marks obtained by XL student are 39 more than the average marks of all the students find mean marks of all the 40 students ​

Answers

Answered by pawanjikherod
0

Answer:

Let the marks scored by 40th student be x

So the average would become

(1950 + x)/40

Given that his marks are 39 more than the average of 40 students

=> x = (1950 + x)/40 + 39

=>

x = \frac{1950 + x}{40} + 39 \\ \\ = > x = \frac{1950 + x}{40} + \frac{1560}{40} \\ \\ = > x = \frac{3510 + x}{40} \\ \\ = > x = \frac{3510}{40} + \frac{x}{40} \\ \\ = > x - \frac{x}{40} = \frac{3510}{40} \\ \\ = > \frac{40x - x}{40} = \frac{3510}{40} \\ \\ = > \frac{39x}{40} = \frac{3510}{40} \\ \\ = > x = \frac{3510}{40} \times \frac{40}{39} \\ \\ = > x = 90

So the boy scored 90 marks

So average =

\frac{1950 + 90}{40} \\ \\ = \frac{2040}{40} \\ \\ = 51

The average is 51

Answer :- 51

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