Manila can make a handcrafted drum in 4 weeks. Zane can also make a similar handcrafted drum in 6 weeks. If they both work together, how many weeks will it take for them to produce 15 handcrafted drums?

Manila makes a drum in 4 weeks = 1/4 drum a week.

Zane makes a drum in 6 weeks = 1/6 drum a week.

X - number of weeks to make 15 drums.

15 = X (1/4 + 1/6)

X = 15 / (1/4 + 1/6) = 15 / (3/12 + 2/12) = 15 / (5/12) = (15/5) x 12 = 3 x 12 = 36 weeks

check: 15 = X (1/4 + 1/6) = 15 = 36 (1/4 + 1/6) = 15 = 36/4 + 36/6 = 9 + 6 = 15