James works as a tutor and a lawn mower. both jobs require that he work at least three hours per week. since james attends school, he can only work 15 hours a week. if james is paid $20 per hour as a tutor and $10 per hour as a lawn mower, which of the following is true about the number of hours he can work as a tutor (t) and lawn mower (m)?
pls
a: james can maximize his earnings by working three hours as a tutor and 12 hours as a lawn mower.
b: the critical points (t, m) for this system of equations are (0, 0), (15, 0), and (0, 15).
c: james can maximize his earnings by working 12 hours as a tutor and three hours as a lawn mower.
d: it is possible for james to work eight hours as a tutor and eight hours as a lawn mower.