8 + 3 + 4) = 8 + (4+3)
what property is this

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer

The sum of the speeds of two trains is 720.2 mph. if the speed of the first train is 7.8 mph faster than the second train, find the speeds of each.

Afarmer has 5 times as many cows as pigs. the farmer only has cows and pigs, and he has 168 animals. how many cows does he have?