She will have 14 toy cars left
13+26+23-10-38=14
(4, 2) ----> ( 2, 1)
(4 - 2, (2 - 1) ----> (2, 1)
That's a vertical -1 and horizontal of -2.
That's the last choice.
.25(4) = 1 gallon
.25(8) = 2 gallons
.25(12) = 3 gallons
.25(16) = 4 gallons
.25(20) = 5 gallons
it would take 20 minutes to remove half the water (aka 5 gallons)