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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Karen has a base salary that is $2100 and does not depends on how many copies she sells.
Additional to the base salary, she gets $50 for each copy she sells, so we can write this additional salary as 50*N, being N the number of copies she sells.
Then, we can write the total pay P as:

Then, if N=22, we can calculate the total pay as:

Answer:
The equation relating P and N is P=2100+50N.
The total pay when she sells 22 copies is $3,200.
Answer:
answer is D
Step-by-step explanation: