Rosa has a goal of running a total of 100 miles this month. each day that she ran, she ran 5 miles. which expression could rosa use to determine how many miles she has left to run after running for d days?

a. 100 - 5d
b. 5d + 100
c. 100/5d
d. 5d - 100

provide an explanation how you came up with the answer, you.

  A.  100 - 5d

Step-by-step explanation:

When d=0, Rosa has 100 miles remaining. That fact eliminates choices C and D, which do not give the value 100 when d=0.

After Rosa runs 1 day, she has 95 miles remaining. That eliminates choice B, which tells you she has 105 miles remaining.

The only viable choice is A.

You could write this expression yourself by realizing that Rosa starts with 100 miles remaining and decreases that amount by 5 each time the value of d increases by 1. That is, the expression 5d represents the number of miles Rosa runs in d days. This number is subtracted from her goal to give the remaining miles, so 100-5d is the number she has remaining of her goal.

s

step-by-step explanation: