Lena is a software salesperson. Her base salary is $1800 and she makes $50 more for every copy of English is Fun she sells. Her total pay, P (in dollars), after selling c copies is given by the following.

P=50c+1800

1. what is the Lenas total pay if she sells 25 copy's?

2. If lenas total pay is 3500 how many copys did she sell?