9514 1404 393
Answer:
12 minutes
Step-by-step explanation:
Let c and h represent the filling times for the cold and hot taps, respectively. When the cold tap is 1/2 open, we presume that means the filling time becomes 2c.
In terms of baths per minute, the relationships are ...
1/c + 1/h = 1/3
1/(2c) +1/h = 1/(3 +1.8) . . . . . 1:48 min:sec is 1.8 minutes
Subtracting the first equation from twice the second, we get ...
2(1/(2c) +1/h) -(1/c +1/h) = 2(1/4.8) -(1/3)
1/h = 2/4.8 -1/3 = 1/12
h = 12
It takes the hot tap 12 minutes to fill the tub alone.
