The sixth-graders at meadowbrook middle school are going on a field trip. the 325 students and adults will ride in school buses. each bus holds 48 people. how many school buses are needed?

Remember that you can do anything to an equation as long as you do it to both sides so

we find how many buses needed
 so basically we need at least 325 people spaces
1 bus=48 people spaces
 therefor
 how many buses= 48 times number of busses > 325
 (> means 'is greater than or equal to')
so 48 times number of busses > 325
divide both sides by 48
number of busses > 325/48
 325/48=6 and 37/48
 number of busses > 6 and 37/48
 the number of busses has to be greater that 6 and 37/48
 number of busses also has to be a whole number
 (imagine renting a fractional bus, "Ok, so I need 6 and 37/48 busses. No, I don't want 7 busses, that'll cost extra. Yes, I know what I'm doing. What?! You can't? Why?! You people are so incompetent. Of course I don't want to rent 7 busses. Were just going in circles. Have a nice day! *hangs up*")
so therefor we round 6 and 37/48 up to 7 busses
 the answe ris 7 busses