If the volumes of two right circular cones are in the ratio 1:4 and their diameters of bases in the ratio 4:5, then their heights will be in the ratio:
A and B together can finish a work in 30 days. They worked for it for 20 days and then B left the work. The remaining work was done by A alone in 20 days more. In how many days can A alone finish the work?