Solution

Multiplying $0.25 by 18 yields $4.50, which is the cost of the 18 pens; and multiplying $0.35 by 100 yields $35.00, which is the cost of the 100 markers. The total cost is therefore Equivalent decimals, such as $39.5 or $39.500, are considered correct. Thus, the correct answer is $39.50 (or equivalent).

Note that the dollar symbol is in front of the answer box, so the symbol $ does not need to be entered in the box. In fact, only numbers, a decimal point and a negative sign can be entered in the answer box.