How many lb are 16 ounces

Ascuba diver was 80 feet below sea level and swam up at a rate of 4 feet per minute. the two solutions show how long it took the scuba diver to reach an elevation of 20 feet below sea level. lydia and max used the methods shown below to find the time it took the diver to reach the new elevation.

Anyone know? will mark brainliest if correct

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39