The watre is 16 inches deep so and you can use our volume calculator to calculate the amount of water in the basement.
A: 40 ft by 28 ft by 16 inches gives 11171 U.S. gallons
B: 16 ft by 22 ft by 16 inches gives 3510.9 U.S. gallons
For a total of 14681.9 gallons. At 50 gallons per minute it will take 294 minutes which is about 5 hours and hence with 2 pumps about 2.5 hours.
I hope this helps,