| A man covered a certain distance at some speed. Had he moved 2 km/h faster, he would have taken 2 h less, if he had moved at 1 km/h slower, he would have taken 2 h more. The distance is |
A) 24 km
B) 28 km
C) 21 km
D) 27 km
Correct Answer: A
Solution :
| Let distance \[=x\,\,km\] and usual rate \[y=1\,\,km/h.\] |
| \[\frac{x}{y}-\frac{x}{y+2}=2\]\[\Rightarrow \]\[\frac{2}{y\,\,(y+2)}=\frac{2}{x}\] |
| \[y\,\,(y+2)=x\] (i) |
| and \[\frac{x}{y-1}-\frac{x}{y}=2\]\[\Rightarrow \]\[\frac{1}{(y-1)y}=\frac{2}{x}\] |
| \[2y\,\,(y-1)=x\] (ii) |
| On dividing Eq. (i) by Eq. (ii), we get \[y=4\] substituting \[y=4\] in Eq. (i), we get \[x=24\,\,km\] |
You need to login to perform this action.
You will be redirected in
3 sec
