Estimating Area Exam Question

Question

Pieces of turf are 1m long by 0.5m wide. Each piece costs £3.79 .

$1 * 0.5 = 0.5\text m^2$

a)Estimate the cost of turf required to cover these spaces.

i) 9.6m by 2.4m

$10 * 2 = 20\text m^2$

$3.79 * 40 = £151.60$

ii) 6.2m by 1.9m

$3.79 * 24 = £90.96$

iii) 4.4m by 2.1m

$3.79 * 16 = £59.64$

But all the answers are wrong where did i go wrong?

Thank You and Help is Appreciated

Answer 1

Hint:

The pieces of turf have to have lengths that are multiples of $1$ metre, and widths that are multiples of $0.5$ metres, since you cannot have fractional parts of a piece of turf. So you need to round to the nearest $1$ metre for the length and $0.5$ metres for the width.

However you need to completely cover the area, so you need to round up as well.

For i), the calculation should be:

Estimated area of turf – $10 m \cdot 2.5 m = 25 m^2$

Number of pieces of turf – $\frac{10 m}{1 m} \cdot \frac{2.5 m}{0.5 m} = 50$

Cost of turf – $50 \cdot £3.79 = £189.5$

Can you do the same for parts ii) and iii)?

Answer 2

What a horrible question. You're supposed to estimate that $0.5m$ side of the piece making it $1m$, so the area of the piece is $1m^2$. Everything else is right.

Answer 3

After trying the question with knowing the answer is £160 I realised that

1 * 0.5m is $0.5m^2$ and £3.79 is rounded to £4

so

i) £4 * 40 = £160

ii) £4 * 24 = £96

and iii) £4 *16 = £64

Thank You for the time of Toby Mak and Rhys Hughes who tried to answer this confusing question as it did help me come to the right direction. c: