Answer:
$5,262.63
Step-by-step explanation:
The computation of the program increase in total spending in economy is shown below:
But before that we need to find out the government spending multiplier is '
= 1 ÷ (1 - MPC)
= 1 ÷ (1 - 0.85) 
= 6.67
 Now 
The increase in total spending is 
 = increase in spending × spending multiplier 
 = $789 billion × 6.67
= $5,262.63
 Hence it would be increased by $5,262.63