Question 139
A group of people needs to be transported from point $A$ to point $B$ by a bus that can carry only half of them. The bus first departs with half of the people while the others start walking. After dropping off the passengers partway, the bus returns, picks up the rest, and continues to $B$. The walking group and the bus all arrive at $B$ simultaneously. The total time taken is twice the time it would take if two buses operated simultaneously. Find the ratio of the time the first group spends in the bus to the time they spend walking.
(Khulan Tumenbayar)
(Khulan Tumenbayar)