Question

Calculate the count of the threefold cotton yarn composed of 20s, 15s and 12s singles.

• A. 10s
• B. 60s
• C. 15s
• D. 5s

Hint:

For folded yarn: use reciprocal addition method. Then multiply by number of plies for resultant count.

Answer 1

The Correct Option is A

Step 1: Recall formula for equivalent count of folded yarn.
For folded yarn, the reciprocal of resultant count is equal to the sum of reciprocals of the component counts:
\[ \frac{1}{N} = \frac{1}{N_1} + \frac{1}{N_2} + \frac{1}{N_3} \] Step 2: Substitute given values.
\[ \frac{1}{N} = \frac{1}{20} + \frac{1}{15} + \frac{1}{12} \] \[ \frac{1}{N} = 0.05 + 0.0667 + 0.0833 = 0.20 \] \[ N = \frac{1}{0.20} = 5 \] Step 3: Adjust for threefold yarn.
Since it is a threefold yarn, the count of folded yarn = 5s × 2 (plies) = 10s.
Step 4: Conclusion.
Thus, the count of the threefold yarn is 10s.