first, lets represent
the gerbil eats 1 food unit
the german shepard eats 14 times of gerbil or 14 food units
together they eat 225 oz per week so
gerbil=1food unit
german shepard=14 food unit
add them together
gerbil+german shepard=15 food unit
15 food unit=225 oz
divide both sides by 15
1 food unit=15 oz
we want to find 14 food unit
15 oz times 14=210 oz
the german shepherd eats 210 oz per week
