Question

the third- and fourth-grade teachers are planning a field trip. there are 173 third graders and 124 fourth graders. each seat on the buses fits 3 students. which expression represents the closest estimate of the number of seats on the buses that are needed for the students? (180 - 130) × 3 (180 + 130) ÷ 3 (175 - 125) × 3 (175 + 125) ÷ 3

Explanation:

Step1: Find total students

First, we need to find the total number of students. There are 173 third - graders and 124 fourth - graders. To estimate, we can round 173 to 175 and 124 to 125. The total number of students is the sum of the number of third - graders and fourth - graders, so the estimated total number of students is \(175 + 125\).

Step2: Calculate number of seats

Each seat fits 3 students. To find the number of seats needed, we divide the total number of students by the number of students per seat. So the expression for the number of seats is \((175 + 125)\div3\). Let's check the other options:

• For \((180 - 130)\times3\): We need the total number of students, not the difference, and we should divide by 3, not multiply, so this is wrong.
• For \((180 + 130)\div3\): The rounding of 173 to 180 and 124 to 130 is not as close as rounding to 175 and 125.
• For \((175 - 125)\times3\): We need the sum of students, not the difference, and we should divide by 3, not multiply, so this is wrong.

Answer:

\((175 + 125)\div3\)