Final answer:
To estimate the cost of 3.9kg of apples at 87p per kg rounded to one significant figure, we round up the first digit of 3.9kg to 4 and calculate the estimated cost as 4kg * 87p/kg to get £3.48.
Step-by-step explanation:
To estimate the cost of 3.9kg of apples at 87p per kg by rounding each value to one significant figure, we will use the rounding rule for significant figures:
- If the digit to the right of the significant figure is 5 or greater, round up.
- If the digit to the right of the significant figure is less than 5, round down.
Let's round 3.9kg to one significant figure. The first digit in 3.9kg is 3 and the digit to the right of the significant figure is 9, which is greater than 5. Therefore, we round up the first digit to 4. The estimated weight of apples is now 4kg. Now, let's calculate the estimated cost:
Estimated cost = Estimated weight * Cost per kg
Estimated cost = 4kg * 87p/kg
Estimated cost = 348p or £3.48 (rounded to two decimal places).