GK Expert Team Solutions for Chapter: Practice Paper, Exercise 15: Set 4

Pipes A and B can completely fill a water tank in 4 hrs and 5 hrs respectively. A pipe C can empty a tank filled completely with water in 3 hrs. Initially the tank is empty and all the pipes are closed. Pipe A is opened first at time t = 0 and pipe C is opened at the instant when the tank is exactly half filled with water. Pipe B is opened after pipe C and at the instant when the tank is exactly one-fourth filled with water. Find the total time taken to fill the tank completely counting from t = 0.

X and Y are stationed at points A and B respectively. Everyday X and Y start simultaneously from A and B to reach B and A respectively. Every day they cross each other at a point R. From point R, the time taken by X to reach B and the time taken by Y to reach A is 36 s and 16 s respectively. One particular day Y started late and during that time X had covered 20 km. Find the distance between the point R and the point where they met on that day.

An urn contains 5 red, 7 blue and 8 green balls. Three balls are selected randomly from the urn without replacement. The probability of drawing balls of the same color is:

Copper and zinc are the only elements in alloys A and B. The ratio of copper and zinc in the alloys A and B is 2:3 and 3:1 respectively. An alloy C is made by mixing alloys A and B. Which of the following can be a possible ratio of zinc and copper in the alloy C?

Sonal and Deepali started swimming towards each other simultaneously from points A and B respectively situated at two ends of a 96 km long stretch of a river. Destinations of Deepali and Sonal are points A and B respectively. Both of them can swim at 12 kmph in still water. When they started, it was high tide and Sonal swam against the stream. As soon as they met, the tide changed to 'low tide' and then Deepali faced the resistance of the stream. Deepali and Sonal took 7 hr 12 min and 8 hr $34\frac{2}{7}$ min to reach their destinations respectively.    [Speed of the stream during high and low tide need not necessarily be the same] If they continue to swim back to their respective starting points after reaching their destinations, then where will they meet during the return journey?[Assume tide changes only once immediately after their first meeting]

Mohan borrowed Rs. 22,500 from two friends Kirti and Lalit. He repaid the amount bororwed from Kirti with an interest at the rate of 11 % p.a. and repaid the amount bororwed from Lalit with an interest at the rate of 12% p.a. The total interest paid for two years was Rs. 4,900. The amount he borrowed from Lalit was:

The average age of the eleven players of a team, standing in a row, is 37.5 years. If the average age of the first six players from the left is 42.8 years while that of first six players from the right is 34.7 years, then find the age of the sixth player from the left.

P is any point in a plane on which a rectangle ABCD having dimensions 12 cm x 8 cm is drawn such that both PAS and PBC are triangles. If PA:PB =3:1, then which of the following can never be the ratio of the length of line segments PC and PB?