Question 19.
Two circular tracks T1 and T2 of radii 100 m and 20 m, respectively touch at a point A. Starting from A at the same time, Ram and Rahim are walking on track T1 and track T2 at speeds 15 km/hr and 5 km/hr respectively. The number of full rounds that Ram will make before he meets Rahim again for the first time is
A
5
B
3
C
4
D
2
Question Explanation
Text ExplanationVideo Explanation
To complete one round Ram takes 100m/15kmph and Rahim takes 20m/5kmph
They meet for the first time after L.C.M of (100m/15kmph , 20m/5kmph) = 100m/5kmph=20m/kmph.
Distance traveled by Ram =20m/kmph * 15kmph =300m.
So, he must have ran 300/100=3 rounds.
Note:
CAT gave both 2 and 3 as correct answers because of the word 'before'.
No video explanation yet — we're on it and uploading soon!
