Teacher is buying pencils for 315 students. The pencils are sold in boxes of tens. How can she use rounding to decide how many pencils to buy?How do I get the answer?

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hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

There are 315 students ,

then the teachers needed 315 pencils.

Since the pencils comes in 10- pecils cases, then she can buy 32 cases .

Then, each student will have 1 pencil and there will be 5 extra pencils.

Then, we will round the pencils needed from 315 to 320

If she buy 1 less case. then there will be 31 cases with 310 pencils and 5 studens will not get any.

Then , the teacher needs to buy 32 cases

william1941's profile pic

william1941 | College Teacher | (Level 3) Valedictorian

Posted on

The teacher has to buy pencils for 315 students. If she has more than 315 pencils, it is fine as there will be a few extra pencils but if she has less than 315 pencils, a few students will not be able to do their work.

Now pencils are sold in boxes that contain 10 pencils each. So the teacher rounds 315 to the next higher number that is divisible by 10. Here it is 320. Therefore she needs to buy 32 boxes of pencils to satisfy the requirement of all the students.

nuke34's profile pic

nuke34 | eNotes Newbie

Posted on

She should round up the # of students to 320 in order to have enough for everyone.10 pencils times 32 boxes =320 pencils...


neela's profile pic

neela | High School Teacher | (Level 3) Valedictorian

Posted on

The problem is telling about the utility and application of rounding.

The number of students = 315.

The number of pencils in a bos = 10.

Since each pencil box has 10 pencils, teacher has to purchase  a number nearest 10  to 315 . There are two nearest 10's: 310 or 320 . But with 310 pencils , it is short of 5 pencils for 315 students, if she gives one pencil to each.

With 320 pencils, she can give one each to 315 students and retain extra 5 pencils.

So the number boxes of pencils each containing 10 pencils to be purchased by the teacher = 320/10 = 32

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