Fruit Prices
| Fruit | Cost (per pound) |
| -------- | ---------------- |
| apples | $1.89 |
| cherries | $5.28 |
| grapes | $2.78 |
Karla is making fresh grape jelly. She buys 18.7 pounds of grapes.
Estimate the total cost.
$2.78(18.7)
Karla will spend about $\square$ on grapes.
Answer (2)
To estimate the total cost of grapes, Karla should round the cost per pound ( $2.78) to approximately $3, and the weight (18.7 pounds) to approximately 19 pounds. Multiplying these gives $57 as an estimated total cost for the grapes.
;
Round the cost per pound to the nearest dollar: $2.78 \approx $3.
Round the amount of grapes to the nearest whole number: 18.7 pounds \approx 19 pounds.
Multiply the rounded cost per pound by the rounded amount of grapes: $3 \times 19 = $57.
Karla will spend about $57 on grapes.
Explanation
Understanding the Problem We are asked to estimate the total cost of 18.7 pounds of grapes that cost $2.78 per pound. To estimate, we will round each number to the nearest whole number.
Rounding the Cost First, we round the cost per pound: $2.78 is approximately $3.
Rounding the Weight Next, we round the amount of grapes: 18.7 pounds is approximately 19 pounds.
Calculating the Estimated Cost Now, we multiply the rounded cost per pound by the rounded amount of grapes to estimate the total cost: 3 \t \t × 19 = 57
Final Answer Therefore, Karla will spend about $57 on grapes.
Examples
Estimating costs is useful in everyday life. For example, when you go grocery shopping, you can estimate the total cost of your items to make sure you stay within your budget. If you are buying 5 items that cost $2.95 each, you can estimate the total cost by rounding $2.95 to $3 and multiplying by 5, which gives you $15. This helps you quickly assess if you have enough money or if you need to remove some items from your cart.
