a. 5000

b. 8000

c. 10000

d. 20000

**Answer:** c. 10000

**Explanation:**

Total votes = a.

This means that, Votes of candidate 1 + Votes of candidate 2 = a

We know that, Votes of candidate 1 = 40% of a = | 40a |

100 |

Hence, Votes of candidate 2 = (100% - 40%) of a = 60% of a = | 60a |

100 |

∴ | 60a | - | 40a | = 2000 |

100 | 100 |

a. 65,550

b. 80,500

c. 87,846

d. 88,550

**Answer:** c. 87,846

**Explanation:**

Tip:

Remember this formula. It is similar to formula for COMPOUND INTEREST.

P = Population; R = Rate of increase or decrease; n = number of years;

'+' = during increase; '-' = during decrease

Remember this formula. It is similar to formula for COMPOUND INTEREST.

Population after n years = P | 1 ± | R | n | ||

100 |

'+' = during increase; '-' = during decrease

Population after 4 years = 60,000 | 1 + | 10 | 4 | ||

100 |

= | 60,000 x 11 x 11 x 11 x 11 | = 87,846 |

10 x 10 x 10 x 10 |

a. 70250

b. 72250

c. 76550

d. 73500

**Answer:** d. 73500

**Explanation:**

Tip:

Remember this formula. It is similar to formula for COMPOUND INTEREST.

P = Population; R = Rate of increase or decrease; n = number of years;

'+' = during increase; '-' = during decrease

Remember this formula. It is similar to formula for COMPOUND INTEREST.

Population after n years = P | 1 ± | R | n | ||

100 |

'+' = during increase; '-' = during decrease

Rate 1 = R1 = 25% (increase);

Rate 2 = R2 = 30% (decrease);

Rate 3 = R3 = 40% (increase)

Population after 3 years = 60,000 | 1 + | 25 | 1 - | 30 | 1 + | 40 | ||||||

100 | 100 | 100 |

= 60,000 | 125 | 70 | 140 | ||||||

100 | 100 | 100 |

a. 60%

b. 70%

c. 80%

d. 90%

**Answer:** b. 70%

**Explanation:**

**Usual Mistake:** Percentage of Students failing in both subjects = 25% + 15% = 40%

But as shown in the below diagram, the students who failed both subjects (10%) are counted twice - Once in 15% (blue circle) and once again in 25% (orange circle).

We need to subtract this double counting.

So students who failed subjects would be = 25% + 15% - 10% = 30%

Remember:

Subtract only once, not twice!

Percentage of students who passed in both subjects = (100 - 30) % = 70%

Item | Expenses out of income |
---|---|

Food | 30% |

House Rent | 35% |

Travel | 9% |

Education | 17% |

a. Rs. 7000

b. Rs. 7100

c. Rs. 7200

d. Rs. 7300

**Answer:** c. Rs. 7200