B

C= 1340.......( 1)

1/2a = 6/1/buckle a =12/1b ... (2)

7/ 1 1B = 2/3C C = 2 1/22b...(3)

Substitute (2) and (3) into (1).

12/ 1 1B

B

2 1/22B= 1340

B=440

will

B=440

Substitute in (2) and (3) respectively.

A=480

C=420

So the number of people who booked version A is 480, the number of people who booked version B is 440, and the number of people who booked version C is 420.