A bank offers 20% compound interest per half year. A customer deposits Rs 2800 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is ______.
Josna takes 4 hrs 30 min in walking a distance and riding back to some place where she started. She could walk both ways in 5 hrs 40 min. The time taken by her to ride back both ways is