# B is what percentage of A

## ФFormula for calculating what percentage of the number B from the number A.

If you know two number A and B and need find, B is what percentage of A, then

P | = | B | · 100% |

A |

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

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

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

## Examples of solving problems: B is what percentage of A

Example 1.

5 is what percentage of 40.
**Solution.**

5 · 100% | = 12.5% |

40 |

**Answer:** 5 is 12.5% of 40.

Example 2.

In store book costs $ 400 and $ 380 on the market. Find what percentage of the market price in relation to the store?
**Solution.**

380 · 100% | = 95% |

400 |

**Answer:** 95%.

Example 3.

The bank deposit put $ 10,000 in a year have profited of $ 1200, what the interest rate was in the bank.
**Solution.** The interest rate is equal to a percentage, which is the profit of the deposit amount

1200 · 100% | = 12% |

10 000 |

**Answer:** the interest rate was 12%.

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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