15 men and 21 women, working together, can do a job in 56 days, while 12 men and 24 women, working together, can do the same job in 64 days. In how many days can the same job be done by 18 men and 24 women, working together?

A

$$47\frac{6}{19}$$

B

$$47\frac{5}{19}$$

C

$$47\frac{9}{19}$$

D

$$47\frac{3}{19}$$