Samuel’s family drank a total of 10.25 gallons of milk in a 13 week period. At this rate, how many gallons of milk will Samuel’s family drink in 52 weeks.
First you find out how many gallons they consume per week, to do so you divide the consumed amount by the passed time (10.25/13) and you'll find they consume 0.788 gallons a week. Next you simply multiply the weekly consumption by the 52 weeks and get 0.788*52=41.
You can also write this as a single equation as (10.25/13)*52.
x / 10.25 = 52 /13
x / 10.25 = 4 multiply both sides by 10.25
x = 41 gallons