To determine how much Tokuji can increase his discretionary spending, let's follow a step-by-step method:
1. Determine the initial and new net income:
- Initial net income: \[tex]$600
- New net income: \$[/tex]650
2. Calculate the increase in net income:
- The increase in net income is [tex]$\$[/tex]650 - \[tex]$600 = \$[/tex]50[tex]$
3. Determine the initial and new savings:
- Initial savings: \$[/tex]80
- New savings: \[tex]$110
4. Calculate the increase in savings:
- The increase in savings is $[/tex]\[tex]$110 - \$[/tex]80 = \[tex]$30$[/tex]
5. Calculate the amount available for increased discretionary spending:
- With the increase in net income and after allocating extra to savings, the amount that can be diverted to increased discretionary spending is [tex]$\$[/tex]50 (increase in net income) - \[tex]$30 (increase in savings) = \$[/tex]20[tex]$
So, the amount by which Tokuji can increase his discretionary spending is:
\[\boxed{\$[/tex] 20}\]
Thus, the correct option is \$20.