Question 600021
Luis's rate of working is 
( 1 job ) / ( t sec )
Javier's rate of working is
{ 1 job ) / ( 3t sec )
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(a)
{{{ t= 30 }}} sec
Javier takes
{{{ 3t = 3*30 }}} sec
{{{ 3t = 90 }}} sec
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(b)
{{{ t = 90 }}} sec
Javier takes
{{{ 3t = 3*90 }}} sec
{{{ 3t = 3*90 }}} sec
{{{ 3t = 270 }}} sec
{{{ 270/60 = 4.5 }}} min
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(c)
{{{ t = 2 }}} min
Javier takes
{{{ 3t = 3*2 }}} min
{{{ 3t = 6 }}} min
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