Question

A pool is being drained at a constant rate. The amount of water is a function of the number of minutes the pool has been draining, as shown in the table. Write an equation in slope-intercept form that represents the function. Then find the water in the pool after two and a half hours. 
Time (mi)       12--------20------50
Volumne (gal) 4962--4754--3974

Answer 1

12a+b=4962
20a+b=4754
8a=-208
a=-26
-312+b=4962
b=4962+312
b=5274
y=-26x+5274
x=0 -- y=5274
y=0 -- 26x=5274, x=80.85 (approx.)

Answer 2

Answer:

Using the first two values in the table, we can first find the slope to write an equation of a line, so we have

[4754 - 4962 ] / [20 - 12 ] = -26

So we have

y - 4754 = -26(x - 20)  

y - 4754  = -26x + 520

y = -26x + 5274

Let's confirm that the amount after 50 minutes is correct

y = -26(50) + 5274  = 3974

So after  2 + 1/2 hrs  (150 min) we have

y = -26(150) + 5274  = 1374 gallons

Step-by-step explanation: