Cracking the Riddle: How Many Cats to Catch 140 Rats in 140 Minutes?

Have you heard the classic riddle: 'If 7 cats can catch 7 rats in 7 minutes, how many cats does it take to catch 140 rats in 140 minutes?'

Understanding the Rate of Catching Rats

To solve this riddle, let's start by understanding the basic rate of catching rats. It is given that:

7 cats can catch 7 rats in 7 minutes. This means each cat can catch 1 rat in 7 minutes.

Finding the Rate per Cat

Therefore, the rate at which each cat catches a rat can be calculated as:

Rate per cat 1 rat / 7 minutes 1/7 rats per minute

Total Rats Caught by One Cat in 140 Minutes

To find how many rats one cat can catch in 140 minutes, we use the rate we just calculated:

Number of rats caught by one cat in 140 minutes (1/7) * 140 20 rats

Calculating the Number of Cats Needed

Now, to find out how many cats are required to catch 140 rats in 140 minutes, we set up the equation as:

Number of cats Total rats / Rats caught by one cat in 140 minutes 140 / 20 7 cats

Therefore, the answer to the riddle is 7 cats.

Application of the Rule of Mathematics

Alternatively, we can apply a simple rule of mathematics to solve this riddle:

M1 * D1 * H1 / W1 M2 * D2 * H2 / W2

M1 7 cats, D1 7 minutes, H1 1 hour, W1 7 rats M2 Unknown, D2 140 minutes, H2 1 hour, W2 140 rats

Solving for M2:

7 * 7 / 7 M2 * 140 / 140

M2 7

So, the number of cats needed is also 7.

Why 7 is the Correct Answer

Even if the scenario sounds unrealistic, the answer can be derived from the given data. With multiple choices, the best answer based on the provided options is 7 cats. This is because the options provided are:

A. 20 cats B. 15 cats C. 10 cats D. 7 cats

The least wrong answer among these choices is 7, as it matches our calculation. In real-world scenarios, to establish a more accurate rate, controlled experiments would be necessary to determine the actual number of cats needed to catch rats within a given time frame.

In conclusion, based on the riddle and provided choices, the answer is:

Final Answer

D. 7 cats

By understanding the rate of catching rats and applying basic mathematical principles, we can confidently solve this intriguing riddle. If you found this interesting, you might also enjoy exploring other classic math puzzles and riddles!