PSA_PRACTICE_QNR29. John and Bill walk towards to each other’s house. If both leave at 10 am, they meet 10 minutes later. If Bill leave 3 minutes later then John, they’ll meet 9 minutes after Bill leaves. How long does it take for Bill to walk to John’s house?
1) 10 minutes
2) 12 minutes
3) 15 minutes
4) 16 minutes
Ans:
Let, John’s and Bill’s houses be A & B respectively and they meet at ‘M’ in the first scenario.
A|———————–M————–|B
Let, John’s and Bill’s speed be ‘j’ and ‘b’ units/minute.
AB= AM+ MB= 10j + 10b= 10(j+b) ……….. (Y)
A|——————————-N——|B
Let, in the second case both meet at point ‘N’; when they meet, John has walked for 12 minutes and Bill for 9 minutes.
AB= AN + NB = 12j + 9b ………..(Z)
From, (Y) & (Z),
10j + 10b = 12j + 9b
=> b= 2j
Using (Y)= AB= 10(3b/2) = 15b
Since, Bill’s speed = b, time taken to cover this distance= 15 minutes. Option (3).
