Help with Means

Hello, can anybody please explain this question to me and show me how to work it out please. :confused:

Q1. Florence recorded her test results in the back of her exercise book.

She says. 'My mean mark in these five tests was 78%'

Unfortunately, Florence noticed that there was an ink blot covering her mark in art. Can you help her to work out her mark for art?





Thanks for you help kalagota but i still don't know what mark florence got in art

Quote:

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Originally Posted by sammyfox07

Hello, can anybody please explain this question to me and show me how to work it out please. :confused:

Q1. Florence recorded her test results in the back of her exercise book.

She says. 'My mean mark in these five tests was 78%'

Unfortunately, Florence noticed that there was an ink blot covering her mark in art. Can you help her to work out her mark for art?

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you know that mean is equal to the sum of the five tests divided by 5..
it was said that 78% was the boy's mean.
therefore, sum of the five tests over 5 is 78%.
but since the fifth one was erased, let it be equal to x.
so, sum of the four exams plus x all over 5 is still 78%.
hence, sum of the four exams plus x = 5* 78% = 390%.
therefore, x= 390% - sum of the four exams.. Ü