Use the Rate-Factor Model for multiplication. The rate is 320 feet per hour, 320 feethour . The hiking team descended the mountain from 1 pm to 5 pm. The net change is a of feet.

increase, 320 feet

decrease, 320 feet

increase, 1,280 feet

decrease, 1,280 feet

The net change is a decrease of 1,280 feet

Step-by-step explanation:

From the question, we understand that the hiking team has a work rate of 320 feet / hour

Now that are descending between the hours 1pm and 5pm, this means that they descended for a total of 4 hours.

Now the total number of feet they have descended will be the number of hours * work rate = 4 hours * 320 feet/hour = 1,280 feet

Thus, the net change is decrease of 1,280 feet

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.

$12. that is my answer.