OnRamps EXPERIENCE COLLEGE BEFORE COLLEGE modeled by 21. The cost C (in dollars) to send m text messages a month on a mobile phone plan is C(m) = 30 if 0Sms 2500 30+0.2(m-2500) if m > 2500 a. How much does it cost to send 1000 text messages per month with this plan? b. How much does it cost to send 90 text messages each day for a month with this plan? c. Explain the terms of the plan verbally. 22. The set of integers as Z = {. . ., -3, -2, -1, 0, 1, 2, 3, .. .}. The greatest integer of x, denoted by [x ], is defined to be the largest integer k with k s x. a. Find [0.625 ], [141 ], L-4.002 ], and [ + 2] b. Discuss with your classmates how [x ) may be described as a piecewise defined function. HINT: There are infinitely many pieces! c. Is La ]+[b]=[a+b] always true? What if a or b is an integer? Test some values, make a conjecture, and explain your result