Question

The average score of Josie had in 6 subjects is 72 and her average score after 2 additional subjects were added is 74.25. if she scored 80 in the 7th subject, what was her score in the 8th subject correct to the nearest whole number?

Answer 1

$\sf\large\underline{Given:}$

• $\sf{The\: average\:score\:6\: subject=72}$
• $\sf{The\: average\: score\:of\:8\: subject=74.25}$
• $\sf{The\: scored\:in\:7th\: subject=80}$

$\sf\large\underline{To\: Find:}$

• $\rm{The\: score\:in\:8th\: subject=?}$

$\sf\large\underline{Solution:}$

• At 1st calculate the total score in 6 subject after that we have to add the score of 2 additional subject]

$\rm{\implies Total\: score\:in\:6\: subject=N\:of\:sub\times\: average\: score}$

$\rm{\implies Total\: score\:in\:6\: subject=6\times\:72}$

$\rm{\implies Total\: score\:in\:6\: subject=432}$

$\rm{\implies Let,\:The\: score\:of\:8th\: subject\:be\:x}$

$\sf\large\underline{Formula\:used}$

$\rm{\implies Average\: score=\dfrac{sum\:of\: score\:in\:all}{Number\:of\:all\: subject}}$

$\rm{\implies \dfrac{432+80+x}{8}=74.25}$

$\rm{\implies \dfrac{512+x}{8}=74.25}$

$\rm{\implies 512+x=74.25\times\:8}$

$\rm{\implies 512+x=594}$

$\rm{\implies x=594-512}$

$\rm{\implies x=82}$

$\sf\large{Hence,}$

$\rm{\implies The\: number\:of\: score\:in\:8th\: subject=82}$

Answer 2

Please find attachment

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