A-clerk-start-from-house -to-tarvel-office-with-speed-12-km

Dikshant Singh

2-7-2018 #ENGINEERING ENTRANCE [PHYSICS]

A clerk start from house to tarvel office with speed 12 km/h and reach his office 3 minute later but next day he increse his spped 1 km/h he raecher office early 3 min find the distance of office.

2 Answered

Reply

Dikshant Singh

2-7-2018

Wrong answer hai
0.6km is correct answer but I don't know from where it comes

Vivek

2-7-2018

Let the original distance and time be D & t
Case 1 - If cleark travels at 12kmp/h, he reaches late 3 min or 3/60 hr or 1/20hr
We can write the same as
t+ 1/20 = D/12
t=D/12-1/20 -----(1)

Case 2 - If clerk increase speed 1km/h at 13kmp/h, he reaches early 3 min or 1/20 hr
We can write the same as
t-1/20= D/13 -----(2)

putting the in 2 from 1

D/12-1/20 -1/20 =D/13

D/12-D/13= 1/20+1/20
13D-12D/156= 2/20
D/156=1/10
D=156/10
D=15.6km

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