A school's new pump can fill the swimming pool in 2 hours, and the old pump takes 5 hours. What is the time required in hours to fill the pool if both pumps are used together? (Enter your answer as mixed number.)

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

higher potential

explanation:

because it is in a high speed so it must move into a of high potential