Agroup of 10 friends will pack bottles of water into an unknown number of coolers for a trip to the beach. each cooler will contain 25 bottles. at the beach, the friends will share the bottles equally. write an expression with one variable to represent the number of bottles each friend will get. then, use your expression to find how many bottles each friend will get if they bring 2 coolers. explain your thinking

Let x by the number of cooler 
since each cooler has 25 bottles
then in total we have 25x 
there are 10 friend in total to divide the bottles equally 
we have 25x/10 this expresses the number of bottles each friend will get
that answers part a) of the question
now for part b)
we are told the friend brought 2 cooler
then we should have 25(2)=50 number of bottles in total
then it goes that each one of the friend will get 5 bottles (50/10)
Done !