Answer:
The correct answer is the base price is $14.50 and surcharge is $2.45 per pound.
Step-by-step explanation:
United Express charges a base price on packages weighing less than or equal to 1 pound and a surcharge for additional pounds.
Let the base price be $b and surcharge be $s.
For a 4 pound package, the customer is billed $21.85. Therefore the equation of his billing looks like b + 3s = 21.85.
For a 19 pound package, the customer is billed $58.60. Therefore the equation of his billing looks like b + 18s = 58.60.
Subtracting both the equation from each other we get 15s = 36.75
⇒ s = $2.45 and b = $14.50.
Thus the base price is $14.50.