Question : X can do a piece of work in 14 days, Y can do the same work in 28 days and Z can do it in 42 days. In how many days can X, Y, and Z together complete the work?

Option 1: $7 \frac{9}{11}$

Option 2: $7 \frac{7}{11}$

Option 3: $7 \frac{5}{11}$

Option 4: $7 \frac{3}{11}$

Question : x, y, and z are 3 values, such that x + y = 12, y + z = 17 and z + x = 19. What is the average of x, y, and z?

Option 1: 10

Option 2: 8

Option 3: 6

Option 4: 4

Question : If $x(x+y+z)=20$, $y(x+y+z)=30$, and $z(x+y+z)=50$, then the value of $2(x+y+z)$ is:

Option 1: 20

Option 2: –10

Option 3: 15

Option 4: 18

Question : A can complete a piece of work in 9 days. B and C can complete the same work in 12 days and 18 days respectively. If A, B, and C work together, then in how many days will they complete the work?

Option 1: 10 days

Option 2: 8 days

Option 3: 4 days

Option 4: 15 days

Question : If 4 men or 6 women can do a piece of work in 12 days, working 7 hours a day. How many days will it take to complete a work twice as large, with 10 men and 3 women working together 8 hours a day?

Option 1: 6 days

Option 2: 7 days

Option 3: 8 days

Option 4: 10 days