The water level of a reservoir is at 27 feet. During a drought the water level falls by 1 1/2 feet per week. Write an equation for water level L after W weeks.

Question

it also needs to be graphed and I have no clue how to do that either please please please help. Nnmmnnmmmmmmmmmmm

Answer 1

level = (initial level) - (rate at which level falls) x (time the level is falling)

 

L(W) = (27 feet) - (1.5 ft/week) x (W)

 

L(W) = 27 - 1.5W

with L in feet, W in weeks

 

This forum is not set up for graphing.  But the graph of L vs. W will be a straight line crossing the vertical axis at (0,27).  To find where it crosses the horizontal axis, set L = 0 and solve for W.

 

0 = 27 - 1.5W ⇒ W = 27/1.5 = 18

 

The line crosses the horizontal axis at (18,0).  Its interpretation is that the reservoir will be fully depleted in 18 weeks.

Answer 2

The equation is

 

L = 27 -(3/2) W

 

Where L = level after W weeks 

For the graph at W= 0 , L = 27 

Draw L on Y axis and W on X axis 

The points on the line are (18,0) and (0,27)

It is a st line with slope = -3/2