Evaluate: cos 20° cos 40° cos 80°
\( \frac{1}{2} \)
\( \frac{1}{32} \)
\( \frac{1}{8} \)
\( \frac{1}{4} \)
On which date is the Constitution Day of India celebrated?
A, B and C can complete a job in 5 days. B, C and D can complete the same job in 10 days. C, D and A can complete the same job in 15 days and D, A and B can complete the same job in 30 days. How long A, B, C and D together will take to finish the job?
8 days
8 \( \frac{1}{2} \) days
7 \( \frac{1}{2} \) days
7 days