A and C can do 25% of the work in 1.5 days, and A and B can do 33.33% of the work in 4 days. The ratio of efficiencies of B to C is 2:7, and B alone can do the whole work in 30 days. C and B start the work and after 'Y' days B left the work and A joins C, after 3 days they both left the work, now If B can complete the remaining work in 3Y days then find the value of Y.