X, Y and Z can complete a piece of work individually in 6 hours, 8 hours and 8 hours respectively. However, only one person at a time can work in each hour and nobody can work for two consecutive hours. All are engaged to finish the work. What is the minimum amount of time that they will take to finish the work?

What percent of water must be mixed with honey so as to gain 20% by selling the mixture at the cost price of honey?

What is the rightmost digit preceding the zeros in the value of $30^{30}$?

Two persons P and Q enter into a business. P puts ₹14,000 more than Q, but P has invested for 8 months and Q has invested for 10 months. If P's share is ₹400 more than Q's share out of the total profit of ₹2,000, what is the capital contributed by P?