Respuesta :

Isolate the r - divide 0.3 from both sides

0.3r = 2.1
(0.3r)/0.3 = (2.1)/0.3
r = (2.1)/0.3
r = 7

C. r = 7 is your answer

hope this helps
C is correct. because r=2.1/.3 is 21/3 and it is 7.
hopes this loves.