Question

Each student in Mr. Grinkov's class is either a junior or a senior. There are 28 seniors in Mr. Grinkov's class. Recently, he took 30 students from his class on a field trip. Of these 30 students, 7/10 were seniors.

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Answer 1

Step-by-step explanation:If there are only juniors and seniors in Mr. Grinkov's class, and there are 28 seniors, then the remaining students must be juniors. We can calculate the number of juniors as follows:

Total number of students = number of seniors + number of juniors

Total number of students = 28 seniors + number of juniors

Since we don't know the number of juniors, we can use a variable to represent it:

Total number of students = 28 + J

where J is the number of juniors.

Now, we know that Mr. Grinkov took 30 students on a field trip, and 7/10 of them were seniors. We can use this information to set up an equation:

Number of seniors on field trip = 7/10 * 30 = 21

We also know that the total number of students on the field trip was 30, so the number of juniors on the field trip must be:

Number of juniors on field trip = total number of students on field trip - number of seniors on field trip

Number of juniors on field trip = 30 - 21 = 9

Now we can use this information to set up another equation:

Total number of students on field trip = number of seniors on field trip + number of juniors on field trip

30 = 21 + 9

This equation checks out, so we know that our calculations are correct. Therefore, there are 9 juniors in Mr. Grinkov's class.