Final answer:
To withdraw at least $145 from an ATM, you must withdraw $160 if the ATM dispenses cash in $20 bills. This is because ATMs typically do not dispense custom amounts, and $145 is not a multiple of $20.
Step-by-step explanation:
To figure out how much money you need to withdraw from a savings account to have at least $145 in cash, you must consider how ATMs dispense money. ATMs typically dispense cash in specific denominations such as $20 or $50 bills. Therefore, you can't withdraw exactly $145 since it's not a multiple of these denominations.
Calculating the minimum amount you need to withdraw is straightforward. You'll need to round up to the nearest denomination that the ATM offers. Assuming the ATM dispenses $20 bills, the smallest amount of cash that includes $145 is $160 because $140 (7 x $20) is not enough, and $160 (8 x $20) is the next increment that covers your needs.
Thus, you must withdraw $160 if the ATM dispenses $20 bills. If the ATM dispenses different denominations, or has an option to dispense $5 bills, you could withdraw $145 exactly (for example, $100 bill, two $20 bills, and one $5 bill).