If a clerk can file 109 documents in half an hour and thirty minutes, how many documents can the person file in 420 minutes?

How is working backward similar to solving an equation?

Richard save $32 in march he saved $48 in april and $38 in may then richard spent $113 on a keyboard how much money does richard have left

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.