Question 1077194
Over the 3 yrs, he improved his pay by 
{{{ 2*300 = 600 }}}
So, he made {{{ x + (x + 300) + (x + 300 + 300) = 3x + 900 }}} where {{{ x }}}
is the amount he made the 1st year
{{{ 3x + 900 = 15900 }}}
{{{ 3x = 15000 }}}
{{{ x = 5000 }}}
The 1st yr he was paid $5,000
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check:
{{{ 5000 }}}
{{{ 5300 }}}
{{{ 5600 }}}
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{{{ 15900 }}} total
OK