Question 1065961
Let {{{ x }}} = weight of the letter in ounces
Let {{{ P }}} = the price of mailing the letter in dollars
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{{{ P = .34 + .21*( x - 1 ) }}} 
( {{{ x >= 1 }}} )
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A 4-ounce letter costs
{{{ P = .34 +  ( 4 - 1 )*.21 }}}
{{{ P = .34 + .63 }}}
{{{ P = .97 }}}
It costs $.97