Can someone help me with this?

Math each whole number with a rational,exponential expression

Acompany charges $0.10 for each letter engraved. bobby plans to spend no more than $5.00 on the engraving on a jewelry box. write and solve an inequality to find the maximum number of letters he can have engraved.

The volume of a box varies directly with its length if a box in the group has a length of 30inches and k=24 what is its volume