What numbers does x equal

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.

Henry is an avid reader, he devours 90 pages in half an hour how many pages has henry read per minute?

Ineed here’s a picture of the question