Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

Rani and Diksha are shopping for clothes.
(i)[3]

Rani purchases 4 identical vests, 3 identical sweaters and 1 coat. Each vest is priced at $5.50 and the coat costs $90. The mean cost of Rani’s 8 items is $29. Find the cost of a sweater.

(ii)[2]

Diksha buys 1 hat and 4 identical shirts. The mean cost of Diksha’s 5 items is $26 and the standard deviation is $0$. Explain how you know that Diksha spends $104 on shirts.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: Set up an equation for total cost using $8 \times \text{mean}$, for example $4\times5.5+3x+90=8\times29$

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