Answers

2014-09-04T10:12:39+05:30
Let the distance travelled at the first part be x km and second part be y km.
CASE 1
total distance = 136 km
x+y=136 --------------------  (1)
CASE 2

FOR 1ST PART
distance = x km
speed = 15 km/hr
time =  \frac{x}{15} hr

FOR 2ND PART
distance = y km
speed = 18 km/hr
time =  \frac{y}{18} hr

 \frac{x}{18} + \frac{y}{15}=6 \\ 15x+18y=1620
3(6x+5y)=1620
6x+5y= 540 -------------------------- (2)

now solve (1) and (2)

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