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Exercises on Section 2

The following exercises provide extra practice on the topics covered in Section 2.

Exercise 4 A combined batch of camera prices

Find the mean price of the batch formed by combining the following two batches, uppercase A and uppercase B , of camera prices.

Batch uppercase A has mean price pounds 80.7 and batch size 10. Batch uppercase B has mean price pounds 78.5 and batch size 17.

Discussion

Mean price of all the cameras is

$fraction open bracket 80 .7 times 10 close bracket + open bracket 78 .5 times 17 close bracket over 10 + 17 end = fraction 2141 .5 over 27 end comma$

which is £79.3 (rounded to the same accuracy as the original means).

Exercise 5 The mean price of fabric

Suppose you buy 8.5 metres of fabric in a sale, at £10.95 per metre, to make some bedroom curtains. The following year you decide to make a matching bedspread and so you buy 6 metres of the same material, but the price is now £12.70 per metre. Calculate the mean price of all the material, in £ per metre.

Discussion

Mean price of all the material is

$fraction open bracket 10 .95 times 8 .5 close bracket + open bracket 12 .70 times 6 close bracket over 8 .5 + 6 end = fraction 169 .275 over 14 .5 end comma$

which is £11.67 (rounded to the nearest penny).

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OpenLearn - Prices, location and spread
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