Question 638399
Let {{{ x }}} = number of 20 cent coins
{{{ x + 7 }}} = number of 50 cent coins
given:
{{{ x*20 + ( x + 7 )*50 = 1610 }}} ( in cents )
{{{ 20x + 50x + 350 = 1610 }}}
{{{ 70x = 1610 - 350 }}}
{{{ 70x = 1260 }}}
{{{ x = 18 }}}
{{{ x + 7 = 25 }}}
You have 18 twenty cent coins and
25 fifty cent coins
check answer:
{{{ x*20 + ( x + 7 )*50 = 1610 }}}
{{{ 18*20 + ( 18 + 7 )*50 = 1610 }}}
{{{ 360 + 1250 = 1610 }}}
{{{ 1610 = 1610 }}}
OK