Question

If 14 men cultivates 42 acres of land in 18 weeks, how many weeks will 21 men working at the same rate take to cultivate 56 acres of land.?

Answer 1

acres = k(men * time)
given: acres = 42, time = 18, men=14
42 = k(14)(18)
k = 1/6

acres = (1/6)(men)(time)
56 = (1/6)(21)(time)
time = 6*56/21 = 16

or:
14 men cultivate 42 acres of land in 18 weeks
1 man cultivates 42/14 acres of land in 18 weeks
21 men cultivate 42/14*21 acres of land in 18 weeks
21 men cultivate 63 acres of land in 18 weeks
21 men cultivate 1 acre of land in 18/63 week
21 men cultivate 56 acres of land in 18/63*56 weeks
21 men cultivate 56 acres of land in 16 weeks

Answer 2

I didn't understand this formula pls explain the procedure, thanks.