i need the equation and this is all positive

Question

a river is 5 feet deep. due to rainfall and resulting runoff from the surrounding hills, the depth of the river rises six and one half feet after three inches of rainfall. assume the depth of he river will continue to rise at this same rate with each new each of rainfall...

Answer 1

Let x = amount of rainfall (inches)

 

Let D = depth of river (feet)

 

Depth of river increases due to rainfall.  Relationship of the depth of increase (in feet) to the amount of rainfall (inches) is:

 

6.5 feet / 3 inches rainfall

 

Depth will increase by (6.5/3)*x

 

Depth of river will be the initial depth plus the amount of increase due to rainfall. So:

 

D = 5 + (6.5/3)*x