A deep-sea exploring ship is pulling up a diver at the rate of 25 feet per minute. The driver is 200 below sea level. How deep was the diver 10 minutes ago?
If the diver is being pulled up at a rate of 25 feet per minute, then in 10 minutes, the diver would have been pulled up 25 * 10 = <<25*10=250>>250 feet.
Since the diver is currently 200 feet below sea level, 10 minutes ago, the diver would have been 250 + 200 = <<250+200=450>>450 feet below sea level. Answer: \boxed{450}.
To determine how deep the diver was 10 minutes ago, we need to subtract the distance the diver has traveled in those 10 minutes from their starting depth.
Given:
Rate of pulling up the diver: 25 feet per minute
Depth of the diver below sea level: 200 feet
To find out how far the diver has traveled in 10 minutes, we multiply the rate by the time:
Distance traveled in 10 minutes = 25 feet/minute × 10 minutes = 250 feet
To find out the depth of the diver 10 minutes ago, we subtract the distance traveled from the starting depth:
Depth 10 minutes ago = Starting depth - Distance traveled in 10 minutes
Depth 10 minutes ago = 200 feet - 250 feet
Since the result is negative, it means that the diver was not below sea level 10 minutes ago, but they were already brought up to the surface.
Therefore, the diver was already at the surface 10 minutes ago.