16Hit1600
AlgebraHardIntercept meaning from two data points

Algebra practice question

A plant nursery's weekly sales S, in dollars, depend linearly on the number of sunny days d that week. In a week with 3 sunny days sales were $150; with 6 sunny days, $210. What do the model's slope and intercept represent?

  1. A. Sales rise $20 per sunny day, and a week with no sunny days would bring $90.Correct
  2. B. Sales rise $60 per sunny day, and a week with no sunny days would bring $150.
  3. C. Sales rise $20 per sunny day, and a week with no sunny days would bring $150.
  4. D. Sales rise $30 per sunny day, and a week with no sunny days would bring $60.

Answer: A. Sales rise $20 per sunny day, and a week with no sunny days would bring $90.

Slope: (210 − 150)/(6 − 3) = 20 per day. Intercept: 150 − 20 × 3 = 90.

Why the other answers are wrong

B. Sales rise $60 per sunny day, and a week with no sunny days would bring $150.
$60 is the change over three days, not one.
C. Sales rise $20 per sunny day, and a week with no sunny days would bring $150.
$150 is the sales at 3 sunny days, not at zero.
D. Sales rise $30 per sunny day, and a week with no sunny days would bring $60.
$30 misreads the slope; (210 − 150)/3 = 20.

More Algebra questions

Not affiliated with the College Board. SAT is a trademark of the College Board.