Question

Suppose that the water level of a river is 34 feet and that it is receding (decreases) at a rate of 0.5 foot per day. (a) Write an equation for the water level, L, after d days. (b) What will be the water level of the river after 30 days?

Answer 1

a) Initially, the level is 34 ft

Decrease of 0.5 ft per day

the actual level = the initial level - (decrease)(days)

in equation

$L=34-0.5\cdot d$

b) in the day 30th

$L=34-0.5(30)=19\text{ ft}$

the level after 30 days is 19 ft