Question

Mac is using a piece of equipment at work and wants to know when it will be necessary to change its air filter. The air filter should be changed after 800 hours of use. On average, the equipment is used 3.2 hours a day. The air filter was last changed 117 days ago. When should it be changed again?

Answer 1

$$\begin{gathered} DearStudent, \\ TotalHourstheequipmentcanbeusedis800 \\ oneday3.2hours \\ Thereforeno.ofdays=\frac{800}{3.2}=250days \\ Ithasalreadybeenusedfor117days. \\ Therefore,itcanbeusedforanother250-117=133days \\ Thustheequipmentneedstobechangedafter133days. \\ Regards \end{gathered}$$