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Aarav walks from his house at 9/2 km/hr andreaches his school late by 8 minutes. Next day,
he increases his speed by 1 km/hr and reaches 8
minutes before school time. How far is the school
from his
house?​

 Apr 28, 2021
 #1
avatar+121048 
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Call his  normal time  to  reach school  =   T

 

And  8 min  = 8/60   hr  = (2/15) hr

 

And  rate x time  =  distance....so....equating distances we  have

 

(9/2)(T  +  2/15)  =  (9/2 +1) ( T - 2/15)

 

(9/2 ) ( T  + 2/15)  =  (11/2) (T - 2/15)

 

(9/2)T  + (9/15)  =  (11/2)T  - 11/15

 

(11/15)  + (9/15)   = (11/2) T  - (9/2)T

 

20/15  =  T  =  (4/3) hr

 

So...the  distance is

 

(9/2)  ( 4/3  + 2/15)   = 

 

(9/2)  ( 22/15)  =  33/5 km  =      6.6 km

 

 

cool cool cool

 Apr 28, 2021

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