Answer:
25−5v2
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Answer:
8 or 9
Step-by-step explanation:
So, you first need to take 4/5 of 400 (320). Then, you can count by 75s for a bit
75students; 2chaperones
150; 4
225; 6
300; 8
now, you have 20 students left over...since one chaperone would watch about 37 kids, you can either divide the remaining kids up among the other chaperones, or you can add one more chaperone to watch the 20 kids. i don't know what the teacher wants, so either 8 or 9 chaperones
8x - 7 = 3x + 9
8x - 3x = 9 + 7
5x = 16
x = 16/5 = 3 1/5
Start by putting two coins on each side of the scale. If one side is higher, then the light coin must be in that pair (use a second weighing to determine which of that pair is the lightest.)
If the initial weighing shows the two pairs to be even, discard those four and go to the three others. Put two of the coins on the scale - one on each side. If one side stays higher, that coin is your light one. If however they are equal, the final unweighed coin must be the lighter coin.