A small submarine starts at –1,260 feet in relation to sea level. Then it descends 5 feet per minute for 12 minutes. What is the new position of the submarine in relation to sea level? –1,260 + (–5)(12) = –1,260 + 60 = –1,200
The submarine is at -1260 ft. It descends 5 ft/min for 12 min. 12 min * 5 ft/min = 60 ft. It descended 60 ft, so you must subtract 60 ft from -1260 ft. -1260 ft + (-5)(12) ft = -1260 ft - 60 ft = -1320 ft
The error in the last line in the problem is that (-5)(12) = -60, not 60. The correct line is: -1260 + (-5)(12) = -1260 - 60 = -1320
