Aptitude Discussion

Q. |
On January 1, 2004 two new societies $s_1$ and $s_2$ are formed, each $n$ numbers. On the first day of each subsequent month, $s_1$ adds $b$ members while $s_2$ multiples its current numbers by a constant factor $r$. Both the societies have the same number of members on July 2, 2004. If $b = 10.5n$, what is the value of $r$? |

✔ A. |
2 |

✖ B. |
1.9 |

✖ C. |
1.8 |

✖ D. |
1.7 |

**Solution:**

Option(**A**) is correct

it is 6 months, from January 1, 2004 to July 2, 2004. So, increase will be 6 times.

No. of members $s_1$ will be in A.P.

On July 2nd , 2004, $s_1$ will have $n+6b$ members

$=n+6×10.5n$

$=64n$

No. of members in $s_2$ will be in $G.P$.

On July 2nd, 2004 Number of members in $s_2=nr^6$

$\Rightarrow 64n=nr^6$

$\Rightarrow r=2$

**Kartik**

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**Pooja**

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why taken increase of member of 6 times..........

Since, from January 1, 2004 to July 2, 2004 it is 6 months. I guess solution mentions that.

I think the solution is wrong as here we are taking increase in people 6 times. But it is given the no. of members increase subsequently so we must take the increase to be 5.