Multiple choice

Directions: The following question is accompanied by statements (I), (II) and (III). You have to determine which statements(s) is/are sufficient/necessary to answer the question. There are two types of pipes, type A and type B. In how many hours can one pipe of type A empty a tank? I. The pipe of type A is 2.5 times broader than the pipe of type B. II. Three pipes of type A and five pipes of type B can empty the tank in 4 hours. III. Six pipes of type A can empty the tank in the same time as 15 pipes of type B can do.

  1. Statements I and II

  2. Statements I and III

  3. Statement II and either I or III

  4. Any two statements

  5. All three statements
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement II provides a rate equation involving both pipe types. Statement I gives the ratio of their breadths (which relates to their flow rates), and Statement III gives the ratio of their efficiencies directly. Combining II with either I or III allows solving for the individual rates.

AI explanation

The objective is to find the time taken by one type A pipe, which requires establishing a relationship between the rates of type A and type B pipes. Statement II provides an equation for their combined work (3/A + 5/B = 1/4), but it cannot be solved for A alone without knowing the ratio between the individual rates of A and B. Either statement I or statement III independently provides this necessary ratio, meaning Statement II paired with either I or III provides a complete system of equations to solve the problem.

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