Answer:
The length of the ribbons in all were 25.3 meters.
Explanation:
Given:
Lengths of the three pieces of ribbon were 10 meters and 9 decimeters, 3 meters and 10 decimeters, and finally 10 meters and 4 decimeters.
Now, to find the length of the ribbons in all.
So, by adding the length of all three pieces we get the length of all the ribbons:



.
Now, converting the decimeters into meters = 23 meters + 2.3 meters = 25.3 meters.
(1 decimeter = 0.10 meter)
(23 decimeter = 2.3 meter.)
Therefore, the length of the ribbons in all were 25.3 metres.