The Brandywine River is at its flood stage of 9 ft. It’s continuing to rain. The next measurement shows that the river has risen 1 1/2 ft. ft. An additional measurement shows that the river has risen 1 5/12 ft. ft. How many more feet does the river need to rise to be at the major flood stage of 13 ft.? Express your answer in simplest.

Answer 1

The river has already risen by 1 1/2 ft + 1 5/12 ft = <<1 1/2+1 5/12=2 7/12>>2 7/12 ft.
To reach the major flood stage, the river needs to rise an additional 13 ft - (9 ft + 2 7/12 ft) = 13 ft - 9 ft - 2 7/12 ft = 1 5/12 ft.
In simplest form, this is equal to <<1 5/12=1 5/12>>1 5/12 ft. Answer: \boxed{1 \frac{5}{12}} ft.