Zoe's video game controller needs a pack of batteries zoe test two brands of batteries brand x runs for 20 hours and brand y runs for 12 hours if zoey plays video games for a 120 hours this year how many fewer packs of brand x what she need than brand y

Set up a systems of equations:
Let P stand for number of packs
Px=120/20
Py=120/12
Px=6
Py=10
10-6=4
She will need 4 fewer.

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.