There are #24# students in the science class of Mr. Sato. He wants to give #3# magnets to each pair of students. He has already given #9# pairs of students their #3# magnets. How many more magnets does he need?

Question

There are #24# students in the science class of Mr. Sato. He wants to give #3# magnets to each pair of students. He  has already given #9# pairs of students their #3# magnets. How many more magnets does he need?

Noah Archer · Accepted Answer

Mr. Sato needs #9# magnets.

AS there are #24# students in the science class, there are #24/2=12# pair of students. Mr. Sato wants to give each pair of students #3# magnets Mr. Sato has already given #9# pairs of students their #3# magnets Therefore number of pairs of students yet to be given magnets is #12-9=3#. For them he needs #3xx3=9# magnets.

Emery Allen · Answer

undefined Mr. Sato has already given magnets to 9 pairs of students, which is a total of $9 \times 3 \times 2 = 54$ magnets. Since each pair consists of 2 students, and each student receives 3 magnets, the total number of magnets given out is calculated by multiplying 9 (the number of pairs) by 3 (the number of magnets each pair receives) and then by 2 (to account for each student in the pair).

Since there are 24 students in total, there are $24 \div 2 = 12$ pairs of students.

To find out how many more magnets Mr. Sato needs, subtract the number of magnets already given out from the total number of magnets needed:

Total number of magnets needed = $12 \times 3 \times 2 = 72$

Number of magnets Mr. Sato still needs = $72 - 54 = 18$

Therefore, Mr. Sato still needs 18 more magnets.