Aptitude Discussion

Q. |
$A,B,C$ and $D$ each had some money. $D$ doubled the amounts with the others. $C$ then doubled the amounts with the others. $B$ then doubled the amounts with the others. $A$ then doubled the amounts with the others. At this stage, each of them has Rs 80. Find the initial amount with $C$ (in Rs). |

✖ A. |
75 |

✖ B. |
80 |

✖ C. |
95 |

✔ D. |
85 |

**Solution:**

Option(**D**) is correct

Before doubling, the amounts $B,C$ and $D$, each of them must have had

\(=\dfrac{80}{2}\)

\(=40\)

$A$ must have then had Rs 80+ Rs 120 = Rs 200.

Similarly, we can work out the amounts with each of them before the other doubled the amounts.

The results are summarized below:

Finally--------> $A(80), B(80), C(80), D(80)$

Before $A$ doubles --------> $A(200), B(40), C(40), D(40)$

Before $B$ doubles --------> $A(100), B(180), C(20), D(20)$

Before $C$ doubles --------> $A(50), B(90), C(170), D(10)$

Before $D$ doubles --------> $A(25), B(45), C(85), D(165)$

**Vivek**

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Thanks dude!

this trick worked!

**Apurva**

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If we start from given information then:

At step 1, all are having 80...means just before it in step 2, A helped others to make their money double. So, in step 2, deduct half of B, C, D and add it to A. At step 3, B helped others to make their money double, so from step 2, deduct half of A, C, D and add it to B.

Do similar thing for C and D till end.

A B C D

80 80 80 80

**Abhishek**

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Do it in the reverse order

$C$ has Rs 85.

Starting from the last stage, each has got Rs 80.

A | B | C | D |
---|---|---|---|

80 | 80 | 80 | 80 |

200 | 40 | 40 | 40 |

100 | 180 | 20 | 20 |

50 | 90 | 170 | 10 |

25 | 45 | 85 | 165 |

**Raju**

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Please make me understand the question...

**Jayanth**

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Dear All,

Any other alternative to solve this problem?

Visualize apurva's method with abhishek's table.. u will get it