I need help

Question

suppose that the water level of a river is 34 feet and that it is receding at a rate of 0.5 foot per day. Write an equation for the water level, L, after days, d. In how many days will the water level be 26 feet?

Answer 1

The rate is the same as slope.  Because the level is receding, the slope will be negative since the level is decreasing.  The initial level of the river is 34 feet.   So the general equation you want is

 

L = -0.5d + 34

 

 

Next, plug in L=26 into the equation to solve for d.

 

26 = -0.5d + 34

 

 

Subtract 34 on both sides of the equation.

 

-8 = -0.5d

 

 

Divide both sides of the equation by -0.5

 

16 = d

 

 

The level will be at 26 feet after 16 days.