# B is P percent of what

## Formula for calculating number A when P percent of it is B

A | = | B · 100% |

P |

For the derivation of this equation using the method of solving problems with percentage

"All" | = | 100% | => | "All" = | "Part" · "100%" |

"Part" | "Part in %" | Part in % |

## Examples of solving problems: find number A when P percent of it is B

Example 1.

40 is 5% of what?
**Solution.**

40 · 100% | = 800 |

5% |

**Answer:** 800.

Example 2.

270 women working in the plant. This is 30% of all workers. How many people work at the plant?
**Solution.**

270 · 100% | = 900 |

30% |

**Answer:** 900 people work at the plant.

Example 3.

How much you need to put on deposit at 10% per annum to a year to make a profit of 1000$.
**Solution.**

1000 · 100% | = 10000 |

10% |

**Answer:** deposit must be 10,000$.

Percent
Percent Definition. Main information
Decimal to Percent. Percent to Decimal
The method of solving problems with percentage

The most common types of problems with percent:
Find P percent of A
B is P percent of what?
B is what percent of A?
Find the number which is greater (less) than a given number by P percent
Find the number A if known number B which greater (less) than A by P percent

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