Question

Lu is stringing beads to make a necklace. Of the entire length of the thread, she is using 2 dm 50 cm for yellow beads, 5 dm 50 cm for green beads, and 1 dm 10 cm for violet beads. What will the total length of the necklace (in mm) be?

• A. 1,800 mm
• B. 1,900 mm
• C. 2,000 mm
• D. 2,100 mm

Answer 1

The correct option is B 1,900 mm

We have to find the length of the necklace in millimeter.

Length of thread for yellow beads = 2 dm 50 cm
Length of thread for green beads = 5 dm 50 cm
Length of thread for violet beads = 1 dm 10 cm

∴ Total length of the necklace will be = 2 dm 50 cm + 5 dm 50 cm + 1 dm 10 cm

Converting dm into mm, we see:

So, 1 dm = 100 mm
⇒ 2 dm = 2 × 100 = 200 mm
⇒ 5 dm = 5 × 100 = 500 mm

Converting cm into mm, we see:
So, 1 cm = 10 mm
⇒ 50 cm = 50 × 10 = 500 mm
⇒ 10 cm = 10 × 10 = 100 mm

∴ Total length of the necklace =

So, the total length of the necklace is 1,900 mm.