Problem: An automobile travels 6a​ feet in r seconds. If this rate is maintained for 3 minutes, how many yards does it travel in the 3 minutes?
Answer Choices:
A. 1080ra​
B. a30r​
C. r30a​
D. a10r​
E. r10a​
Solution:
D (yards) =R (yards per minute) ×T (minutes)
D=60r​31​⋅6a​​⋅3=r10a​