Problem #4: Under Verizon's family plan, customer can have multiple cellphones under one plan. Let's say we have a newlywed couple (Cameron and Bellamy) with no human kids, thus they have two service lines. If we let random variables C and B represent the proportions of time that Cameron and Bellamy use their phones, respectively. The joint probability density function of the couple service line usage is given by: fa(2+5% f(c,b) = - + b) 0c 1,0 b 1 otherwise Question # 24: Find the expected value of C, E(C). Question # 25: Find the expected value of B, E(B). Question # 26: Find the expected value of 3C + B. Question # 27: Find the expected value of CB.