Let A, B, and C be the centers of the three circles.
The distance from A to B is a straight-line distance that included the radius of the circle A and the radius of the circle B; thus, it will be 10 cm long. So will the distances from A to C and B to C, for a total distance of 30 cm.
These distances, from A to B, B to C, and C to A, are the same lengths as the lengths of the straps which are not touching the circles.
Now for the distances that wrap around the circles: for circle A, the straps wraps around 1/3 of the pipe, so its length will be 1/3 of the circumference of the circle: (1/3)(2·π·r) = (1/3)(2·π·5) = (1/3)(10π).
Similarly for wrapping around circles B and C. (1/3)(10π) + (1/3)(10π) + (1/3)(10π) = 10π
Total length for each: (10π + 30) cm
Total for both: (20π + 60) cm
[For each, the length will be one circumference of a circle plus three diameters.]