+1347 If Samson is filling a bathtub with COLD water, it will take him 6 minutes and 40 seconds, and if he fills it with HOT water, it will take him 8 minutes. If draining the tub takes 13 minutes and 20 seconds, how many minutes will it take to fill up the bath tub with both HOT and COLD water running while the plug is out, so the water is constantly draining?
+128474 6 minutes 40 sec = 400 sec
So.....each second the cold water fills 1/400 of the tub
8 minutes = 480 sec
So....each second the hot water fills 1/480 of the tub
And 13 min 20 sec = 800 sec
So....each second, 1/800 of the tub is drained
So....we need to solve this.....where x is the number of seconds it takes to fill the tub
(1/400)x + ( 1/480)x - (1/800)x = 1
(2/800)x + (1/480)x - (1/800)x = 1
(1/800)x + (1/480) x = 1
[ 480 + 800] x / { 800 * 480) = 1
x = (800 * 480) / { 480 + 800) = 300 sec to fill the tub = 5 minutes
