Blue whale calves can gain weight at a rate of 200 pounds per day. Two particular calves weigh 6000 pounds and 6250 pounds at birth

Question

What type of relationship exits between the linear equations for “total weight” (w) as a function of “number of days” (d)? What do these lines have in common?

Answer 1

The passage states that the two calves weigh 6000 and 6250 pounds at birth. We can treat these values as our y-intercept, since at x=0 (or in this case, day 0) the weight of the whale is 6000 and 6250.

The passage also states that both whales grow at a rate of 200 pounds per day. We can treat this value as our slope for both whales.

From this we can generate an equation for each whale:

w₁ = 200d + 6000

w₂ = 200d + 6250

As we can see, the linear equations are similar in that they have the same slope, but differ in the y-intercept. This means the lines are parallel.