Atennis instructor chargers $40 for each one hour lesson and $25 for each half hour lesson if the instructors i come from 35 lessons was $1115 how many one hour lessons did she give?

Joe has a rectangular chicken coop. the length of the coop is 4 feet less than twice the width. the area of the chicken coop is 510 square feet. what is the length of the chicken coop?

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

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.