Consider each of the following independent situations:

Required:

For each situation, calculate the missing amount.

$\backslash$table$[[,,\backslash$table$[[$ining$],[$ined$],[$ings$]],,\backslash$table$[[$come for$],[$Year$]],,,,\backslash$table$[[$ding$],[$ained$],[$nings$]]],[$a$.,$$$,320,000,$$$,120,000,$$$,20,000,$$$,420,000],[$b$.,$$$,540,000,$$$,230,000,,,$$$,700,000],[$c$.,$$$,290,000,,,$$$,50,000,$$$,360,000],[$d$.,,,$$$,170,000,$$$,30,000,$$$,490,000]]$