There are 600 students including the seventh and eighth graders at the party.
This problem uses the concept of percentages to define the conditions that are laid in front of us.
Let the original number of students be S , and the number of seventh graders be = 0.60S
We know that percent is used to convey the mathematical term of a fraction multiplied by 100.
Total students after 20 eighth graders arrive = S + 20
And we have that
Number of seventh graders / total number of students = 58%
.60S / [ S + 20 ] = .58 we multiply both sides by S + 20
0.60S =0 .58 [ S + 20]
.60S = .58S + 11.6 we subtract 0.58S from both the sides
0.02S = 11.6 we divide both the sides by .02
S = 11/6 / 0.02 = 580
So the total number of students = 580 + 20 = 600 .
Hence there are 600 students at the party at that time.
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Answer:
The first one is -2x^2 - 21x + 4, the second one is -15 (I think, not 100% sure), the third one is 4xyz + 3yz + 5x - 4 (also not 100% on this one)
Amount paid for the first book is $17.
Amount paid for the second book is 0.75 x 8 = $6
Total amount paid = $17 + $6 = $23
Total full cost of the two books = $17 + $8 = $25
Amount of discount = $25 - $23 = $2
% reduction =

Therefore, the <span>percent of the total cost of the two books reduced during the sale</span> is 8%
But how many laps did she walk