Which shows a correct order to solve this story problem?

isabel rode her bike 18.9 miles this week. she rode her bike 3 times farther last week than this week.

how far did isabel ride her bike in the two weeks?

a.
step 1 multiply 18.9 × 3.
step 2 subtract 18.9 from the product.

b.
step 1 multiply 18.9 × 3.
step 2 add 18.9 to the product.

c.
step 1 divide 18.9 by 3.
step 2 add 18.9 to the quotient.

d.
step 1 divide 18.9 by 3.
step 2 subtract 18.9 from the quotient.