Three friends Alison Beth and Cat are standing for school captain. The probability of Alison get elected is 3/8. The probability that Alison or Cat elected is 7/10.Who is most likely to get elected?

I’m stuck on this equation, anyone got the answer?

Can someone explain to me how to do

Ben frank is an electrician who installs lighting fixtures. he charges (in dollars) his clients 15h+40f15h+40f where hh is the number of hours worked and ff is the number of fixtures installed. how much does ben frank charge when he works 77 hours and installs 99 fixtures?