The answer is 300th caller.
to find the answer you have to take the LCM of all three numbers of callers that are 15,25 and 100
so, lets take the LCM
5 15, 25, 100
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5 3, 5, 20
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3 3, 1, 4
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4 1, 1, 4
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1, 1, 1
Now ,multiply the numbers 5,5, 3 and 4.
5 x 5 x 3 x 4 = 25 x 12 = 300
The Answer in this question is 1,346
Y = -2.5x + 45
That's your equation. Your y-intercept would be 45 because that's what she started with. It would be a negative slope as well.