Rainee's Stuck!

Which is J = rb solved for r? a. r = j/4b b. r = 4b/j c. r = j - 4b d. r = j/b I got "a". Which is M = 300J/P solved for J? a. J = 300PM b. J = 300M/P c. J = 300/PM d. J = PM/300 I got "d". So do they both look right? Or not? Plz tell me! I'd like that A...