Plz help me if you are good at algebra!!

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

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?