The value of y varies directly with x. when y = 25 x = 3/4. what is the value of y when x is 4 7/8

y = 161

Step-by-step explanation:

You can make this more visually understandable first:

y =  25   =  ?  

x  =  3/4   = 4

The change from 3/4 to 4 7/8 is 13/2, so the change between 25 and ? must be 13/2 as well.

25 * 13/2 = 325/2

                = 162 1/2

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50