Aptitude Discussion

Q. |
On a scale that measures the intensity of a certain phenomenon, a reading of $n+1$ corresponds to an intensity that is 10 times the intensity corresponding to a reading of $n$. On that scale, the intensity corresponding to a reading of 8 is how many times as great as the intensity corresponding to a reading of 3? |

✖ A. |
$500$ |

✖ B. |
$3^5$ |

✔ C. |
$10^5$ |

✖ D. |
$50$ |

**Solution:**

Option(**C**) is correct

$n=8$ implies $10^8$

$n=3$ implies $10^3$

Hence, $10^8 /10^3= 10^5$ will be required.

**Edit:** For a solution with a different approach, visit **KARTIK's comment.**

**SWARUP**

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**KARTIK**

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Question is right but i guess explanation is bit confusing.

Suppose reading corresponding 1 $= x$ i.e any number reading corresponding to $1+1$ i.e $2 = 10x$

For $3 = 10*10x$

For $8 = 10^7x$

Divide reading corresponding to 8 by reading corresponding to $3 = 10^5$

**Abhishek**

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lets say at a reding of $n$ the intesity be $x$. than at next reading comes out to be 10 times of previous intesity...that is $10*x$.

now u dont need to add these eaquation like this :

n--->x

(n+1)--> 10*x

-----------------

2n+1 ----> 11x

u cant add them like this ...for instance let

$n=1$ than intensity be $x$

$n=2$ than intensity will be $10*x$ and if u add them according to above than it turns out to be

$n=3$ intensity will be $11x$...which is not true

bcause at $n= 3$ the intensity is 10 times of the

previous one which is $n=2$-->$10x$. thus it will be $100*x$.

**Rahul**

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as you are saying for reading 1 had a value of 10 but how can take it as it is 10.

it is giving as equation :-

$n+1 = 10 \times n$

so by putting 8 and 5, i am getting 50 as answer.

**Barun**

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well it's not that difficult.. It basically tells us that each number on the scale is 10 times the intensity of the previous number.

For ex. if a reading of 1 had a value of 10, then a reading of 2 would have a value of $10*10$, a reading of 3 would have a value of $10*10*10$ and so on.

So, if we want to compare a reading of 8 to a reading of 3, we've gone up by 5 ranks of intensity, which means we're multiplying by $10*10*10*10*10 = 10^5$.

**Animesh**

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don't really understand the question...

ANS 10^5

N------>Let ---> X

N+1-------------> 10X

FOR 3 ---LET--> Y

4------------>10Y

5------------->100Y

8------------>10^5Y