Question

In the following coded arithmetic questions certain symbols are used with the following meaning: I. P @ Q means add P to Q. II. P # Q means subtract Q from P. III. P $ Q means multiply P with Q. IV. P ^ Q means divide P by Q. Now study the given information and answer the questions following it. Three persons A, B and C complete a work in 40 days. B and C together are 5/4 times as efficient as A and B together. On the other hand, A and C together are 7/5 times as efficient as B and C together.