Anjali can complete a job in 10 days. Banu can do it in 5 days. In how many days can the job be done, if they work together?

Given,

Anjali can do a work in 10 days and Banu can do a work in 5 days.

LCM of 10 and 5 is 50.Therefore total jobs to be completed is 50.

Anjali $${10}\times{5}$$ = 50 (Therefore, Anjali can do 5 works per day)

Banu $${5}\times{10}$$ = 50 (Banu can do 10 works per day)

Both together can do $${5} + {10}$$ = 15 works per day

for three days $${15}\times{3}$$ = 45 works can be completed

balance 5 work can be calculated as $$\frac{5}{15}$$ = $$\frac{1}{3}$$

Option is given in hours, so to convert it into hours $${\frac{1}{3}}\times{24}$$ = 8hours

Hence total time taken is 3days 8 hours