# Maths 9-1 GCSE Exam Style Question HELP!!

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Can anyone guide me through the following question...

Pete records all his maths test scores.

Each score is a mark out of 100.

After 9 tests his mean score is 59

After 10 tests his mean score is 58.5

After 11 tests his mean score is 60

Work out the difference between his scores on the 10th and 11th tests.

Pete records all his maths test scores.

Each score is a mark out of 100.

After 9 tests his mean score is 59

After 10 tests his mean score is 58.5

After 11 tests his mean score is 60

Work out the difference between his scores on the 10th and 11th tests.

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#2

(Original post by

Can anyone guide me through the following question...

Pete records all his maths test scores.

Each score is a mark out of 100.

After 9 tests his mean score is 59

After 10 tests his mean score is 58.5

After 11 tests his mean score is 60

Work out the difference between his scores on the 10th and 11th tests.

**NothingButWaleed**)Can anyone guide me through the following question...

Pete records all his maths test scores.

Each score is a mark out of 100.

After 9 tests his mean score is 59

After 10 tests his mean score is 58.5

After 11 tests his mean score is 60

Work out the difference between his scores on the 10th and 11th tests.

**After 10 tests his mean score is 58.5**

Working backwards, what's his total score over the 10 tests?

**After 11 tests his mean score is 60**

Working backwards, what's his total score over the 11 tests?

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#3

**NothingButWaleed**)

Can anyone guide me through the following question...

Pete records all his maths test scores.

Each score is a mark out of 100.

After 9 tests his mean score is 59

After 10 tests his mean score is 58.5

After 11 tests his mean score is 60

Work out the difference between his scores on the 10th and 11th tests.

Then for the 10 tests, we can say that he got amount of marks on the 10th test and so we get and you can work out itself - repeat similarly for the 11th test.

The reason for A+b is because A is the total of the first 9 tests, and b is the total of the 10th test, so adding these two together gives us the total of the first 10 tests which is what we want in order to get our mean score.

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(Original post by

Working backwards, what's his total score over the 10 tests?

Working backwards, what's his total score over the 11 tests?

**notnek**)**After 10 tests his mean score is 58.5**Working backwards, what's his total score over the 10 tests?

**After 11 tests his mean score is 60**Working backwards, what's his total score over the 11 tests?

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#5

(Original post by

How can I work backwards because it is a mean so its an average..idk what the averages are

**NothingButWaleed**)How can I work backwards because it is a mean so its an average..idk what the averages are

So if you work backwards, the total score must have been 585 because 585/10 = 58.5. Does this make sense?

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(Original post by

Let's denote the sum of the scores from the first 9 tests by then we know that and so we have

Then for the 10 tests, we can say that he got amount of marks on the 10th test and so we get and you can work out itself - repeat similarly for the 11th test.

The reason for A+b is because A is the total of the first 9 tests, and b is the total of the 10th test, so adding these two together gives us the total of the first 10 tests which is what we want in order to get our mean score.

**RDKGames**)Let's denote the sum of the scores from the first 9 tests by then we know that and so we have

Then for the 10 tests, we can say that he got amount of marks on the 10th test and so we get and you can work out itself - repeat similarly for the 11th test.

The reason for A+b is because A is the total of the first 9 tests, and b is the total of the 10th test, so adding these two together gives us the total of the first 10 tests which is what we want in order to get our mean score.

So b = 54

Then for the 11th...

\displaystyle\frac{531+54+c}{11} = 60

Hence, c = 75

Would the difference be 75?

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#7

(Original post by

Perfect, Thanks for that, really appreciate it!

So b = 54

Then for the 11th...

\frac{531+54+c}{11} = 60

Hence, c = 75

Would the difference be 75?

**NothingButWaleed**)Perfect, Thanks for that, really appreciate it!

So b = 54

Then for the 11th...

\frac{531+54+c}{11} = 60

Hence, c = 75

Would the difference be 75?

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oh so do I have to take away c from b?

Also, how do people get the fraction signs, and the root signs, etc??

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#9

(Original post by

No it's 21,

oh so do I have to take away c from b?

Also, how do people get the fraction signs, and the root signs, etc??

**NothingButWaleed**)No it's 21,

oh so do I have to take away c from b?

Also, how do people get the fraction signs, and the root signs, etc??

You're forgetting to use in your LaTex formatting.

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(Original post by

is the score on the 10th test and is the score on the 11th test. To find the difference between 11th and 10th test scores you need to take one away from the other, so .

You're forgetting to use in your LaTex formatting.

**RDKGames**)is the score on the 10th test and is the score on the 11th test. To find the difference between 11th and 10th test scores you need to take one away from the other, so .

You're forgetting to use in your LaTex formatting.

it works thanx!

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