here is a feel good TSD prob:
two trains 100m apart start moving towards each other at the same time. A bird flies from the faster train towards the slower one starting at the same time when the train starts. the velocities of the 2 trains and the bird are in GP, the bird being the fastest. the bird reaches the slower train in 10 second and the immediately flies back towards the faster train. it continues this till the two trains meet after 50/3 seconds.
1. after how many seconds does the bird reach the faster train?
2. what will be the total distance traveled by the bird till the two trains meet?
and here is a Q i need help:
A and B are moving alternatively towards each other at their respective constant speeds. A moves first for 1 min, B moves for 2 min then A for 3 min then B moves for 4 mins and so on such that B takes the last move. A and B's speeds are in the ratio 2:1 respectively and B alone can cover the initial distance between A and B in 80 mins. find the time taken by A and B to met each other.
1. 45 mins 2. 55 min 3. 40 min 4. 36min
here is how i went about solving:
both A and B together cover the distance 80x when they meet.
so,
2(1+3+5+..n)+2(1+2+3+..n) = 80
n(2+(n-1)2)+n(n+1) =80
3n^2+n-80=0
solving this equation i get n= -5 or 16/3
pls let me know where i made the miss..
IN MURPHY I TRUST 
Linear Mode
