If 2 tic equals 3 tacs and 2 tacs equal 7 tocs, what is the ratio of one tic to one toc? Choose the correct choice from the following answers.
A) 15 / 2	B) 6 / 5	C) 21 / 4	D) 3 / 10	E) 1 / 15

Rationale: 2 tic = 3 * tac and 2 * tac = 7 * toc ; 4 * tic = 6 * tac and 6 * tac = 21 * toc - - > 4 * tic = 21 * toc - - > tic / toc = 21 / 4 . answer : c .
Answer: C