ratio and propotion

Question

A and B together can perform a work in 12 days. A can complete it in 21 days. Both of them started to do the work but A left after 6 days. In how many days B can complete the remaining work ?

Answer 1

The speed em werk: (1/a)+(1/b)=1/12

speed av a=1/21=0.047619047

kombined speed=1/12=0.0833333

speed av b=0.083333-0.047619047=0.0357142=1/28 daes

after 6 daes tugether, get half the werk dun, so half left

now b werk alone tu du (1/2), so it take him 14 daes more

Answer 2

what is the ratio between 82815 and 59696