Final answer:
Larry's line of 5 wooden boards, each 0.1 meters long, will be 0.5 meters in total. For Juliana, she can measure 200 cm with a meter stick by using it twice, as 200 cm is twice the length of the meter stick.
Step-by-step explanation:
If Larry has wooden boards each 0.1 meters long and he lays 5 boards end-to-end, then the total length of the line of boards can be found by multiplying the length of one board by the number of boards. We perform the calculation as follows: 0.1 meters x 5 = 0.5 meters. Therefore, the line of wooden boards will be 0.5 meters long.
Regarding Juliana's situation, since a meter stick measures 1 meter or 100 centimeters, it can be used to measure a length of 200 centimeters by simply using it twice. Since 200 centimeters is twice the length of a meter stick, she could mark the length of the meter stick twice on the board to get the desired measurement of 200 centimeters.