A preformed piece of coal weighs $100 \mathrm{~g}$ correct to the nearest $5 \mathrm{~g}$. A bag contains 30 pieces of preformed coal.
Complete the sticker to attach to this bag of coal.
This bag of coal weighs at least $\mathrm{kg}$ (4 marks)
This bag of coal weighs at least
Answer
\(\boxed{This\ bag\ of\ coal\ weighs\ at\ least\ 2.85\ kg\ and\ at\ most\ 3.15\ kg}\)
Step 1 ：Find the minimum and maximum weight of each piece of coal: \(min = 95g\), \(max = 105g\)
Step 2 ：Multiply the minimum and maximum weight by the number of pieces in the bag (30): \(min_{bag} = 95g \times 30 = 2850g\), \(max_{bag} = 105g \times 30 = 3150g\)
Step 3 ：Convert the minimum and maximum weight of the bag to kilograms: \(min_{bag_{kg}} = 2.85kg\), \(max_{bag_{kg}} = 3.15kg\)
Step 4 ：\(\boxed{This\ bag\ of\ coal\ weighs\ at\ least\ 2.85\ kg\ and\ at\ most\ 3.15\ kg}\)
