PSA_LEVEL-UP_QNR38. Subhash and Kajal are competing in a 1000 m race. The ratio of their speeds is 4:5. If Subhash has a start of 100 m, then who wins and by how much?
a) Subhash wins by 100 m.
b) Kajal wins by 150 m.
c) Kajal wins by 100 m.
d) Subhash wins by 50 m.
Whereas Kajal has to run the entire 1000 m, Subhash has a lead of 100 metres and thus, has to run 1000-100 or 900 metres.
Speed ratio for Subhash and Kajal = 4:5 = 8:10 = 800:1000
Distance ratio for Subhash and Kajal= 900:1000
As you can observe in the two ratios, the denominator is expressed as same while there is 100 difference in the numerator. You can say at this point that Kajal wins the race by 100 m.
Alternatively, assume that the speeds are 4 m/s and 5 m/s.
Time taken by Kajal to finish the race = 1000/5 = 200 seconds.
In 20 seconds, Subhash has covered 200*4= 800 m only. Therefore he falls short of 100 metres when Kajal wins the race. Option C.