Question 1006292
They drove:{{{ 50 + 3 + 10 + 80 = 143 }}} mi
{{{ 143*2 = 286 }}}
$286 is the cost of gas going to grandma's house
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The trip back from grandma's is a little different.
The trip they made going back to the restaurant 
wasted {{{ 10 }}} mi going back and they needed to
drive {{{ 10 }}} miles to get back to the place
where they turned around, so {{{ 20 }}} mi were 
extra miles {{{ 143 - 20 = 123 }}} is the return miles
{{{ 143 + 123 = 266 }}} total miles
{{{ 2*266 = 532 }}}
$532 was spent on gas going and coming back