From a point P on the ground, the angle of elevation of the top of a 10m tall building is 30°. A flag is hoisted at the top of the building and the angle of elevation of the top of the flagstaff from P is 45°. Find the length of the flagstaff (Take √3 = 1.732)
5 men, 6 women and 4 children can complete a work in 10 days. 6 women and 6 children can do it in 20 days, while 2 men and 6 women can do it in 18 days. In how many days will 2 men and 1 woman will complete the same work?
Two pipes can fill a tank in 15 hours and 4 hours, respectively, while a third pipe can empty it in 12 hours. How long (in hours) will it take to fill the empty tank if all the three pipes are opened simultaneously?