Let's solve the problem step by step.
1. Identify the money Frank has already saved each month and calculate the total amount saved up to now:
- January: \[tex]$100
- February: \$[/tex]80
- March: \[tex]$50
2. Calculate the total amount Frank has saved by adding the amounts saved each month:
\[
\text{Total Amount Saved} = \text{January Savings} + \text{February Savings} + \text{March Savings}
\]
\[
\text{Total Amount Saved} = 100 + 80 + 50
\]
\[
\text{Total Amount Saved} = 230
\]
3. Determine the total amount needed for college, which is given as \$[/tex]1,800.
4. Calculate the remaining amount Frank needs to save by subtracting the total amount saved from the total amount needed:
[tex]\[
\text{Amount Needed} = \text{Total Amount Needed} - \text{Total Amount Saved}
\][/tex]
[tex]\[
\text{Amount Needed} = 1800 - 230
\][/tex]
[tex]\[
\text{Amount Needed} = 1570
\][/tex]
Therefore, Frank needs to save \[tex]$1,570 more to reach his goal of \$[/tex]1,800 for college.