Who want 2 sing wit meh

Aswim teacher sells lesson packages. the best deal has the highest ratio of lessons to total cost.swim lesson packagesnumber of lessons total cost$10$4010 1 $8015$80which package is the best deal? l lesson for $105 lessons for $4010 lessons for $8015 lessons for $80mark this and returnsave and exit

How do i do this activity, is appreciated

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a