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Maths Puzzle
Q. In a 100m race, if A gives B a start of 20m then A wins the race by 5 sec. If A gives B a start of 40m the race ends in a dead heat. How long does A takes to run 200m?
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- sorry Mr. LSINDHU i found the answer and the concept that you have applied here is little bit wrong.
the answer is here
Let time taken by A to comple race= t sec for 100m
speed of A = 100/t
then time taken by B = t+5 sec for 80m
in case 2 the time taken by B to complete 60m will be (t+5)*60/80 =3(t+5)/4 sec
so time taken by A to complete 100m is also 3(t+5)/4 sec as both of them reached at same time in case2
in both the case A has run 100m. and time taken to cover is also same as his speed does not change.
so equating the time in both case we get
t = 3(t+5)/4
=> 4t = 3t + 15
=> 4t-3t = 15
=>t=15 sec.
so time taken to cover 100m by A is 15 sec.
so time taken to cover 200m by A is 15*2 = 30 sec. (ans)
hope, you like my solution friend
- 11 years agoHelpfull: Yes(1) No(0)
- the question simply means that a beats b by 20m or 5sec.
so a takes 50sec to run 200m. - 11 years agoHelpfull: Yes(0) No(0)
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