#### Principal (initial amount), P = 4,000

#### Annual simple interest rate, R = 3%

#### From date: Jul 11, 2017

#### To date: Aug 10, 2017

#### Duration, T = 30 days

#### Commission fee (withdrawal or payment), F = 1%

#### No. of days in a year, N = 365

## I = Simple interest:

#### I = (P × R × T) ÷ N =

#### (4,000 × 3% × 30) ÷ 365 =

#### (4,000 × 3 × 30) ÷ (365 × 100) =

#### 360,000 ÷ 36,500 ≈

#### 9.86301369863 ≈

#### 9.86

## B = Amount earned before deducting the

commission fee (withdrawal or payment):

#### B = P + I =

#### 4,000 + 9.86301369863 =

#### 4,009.86301369863 ≈

#### 4,009.86

## D = Amount earned after deducting the

commission fee (withdrawal or payment):

#### D = B - F =

#### B - F% × B =

#### (1 - F%) × B =

#### (1 - 1%) × 4,009.86301369863 =

#### 99% × 4,009.86301369863 ≈

#### 3,969.764383561644 ≈

#### 3,969.76

## Pr = Investment profit:

#### Pr = D - P =

#### 3,969.764383561644 - 4,000 =

#### - 30.235616438356 ≈

#### - 30.24