Question

A tiling company completes two jobs. The first job has $1200 in labor expenses for 40 hours worked, while the second job has $1560 in labor expenses for 52 hours worked. The relationship between the labor expenses and the hours worked is linear. Which equation can be used to calculate the y-intercept of the linear equation? 1200 = 40 (40) + b 1560 = 30 (40) + b 1560 = 30 (52) + b 1200 = 52 (30) + b

Answer 1

The slope (change in y/change in x) of the line is (1560 - 1200)/(52 - 40), which is equal to 30. We can plug this into the equation y = mx + b using either the point (40, 1200) or (52, 1560). The slope is represented by m and the y - intercept by b. Therefore, the two possible equations you could use are:

1200 = 30(40) + b

or 1560 = 30(52) + b

Using either equation, you'll get that b is equal to 0, which makes sense in the context of the problem, since it's reasonable to expect that the labor expenses would be 0 for 0 hours worked.