Question

Finding Initial Value Using a Table
A 2-column table with 4 rows. Column 1 is labeled Number of Weeks with entries 4, 5, 6, 7. Column 2 is labeled Weight (pounds) with entries 16, 18.5, 21, 23.5.

The table to the right displays the weight progress of a puppy at the end of week 4. If the relationship between time and weight is linear, how much did the puppy weigh at birth?
5.5 pounds
6 pounds
7.5 pounds
16 pounds

Answer 1

Between each week the puppy gains 18.5−16 = 2.5 pounds (and 21−18.5 = 2.5, etc.), so the slope is 2.5 lb/week. At week 4 the puppy is 16 lb, so at birth (week 0): 16 − 4(2.5) = 6 pounds.