#### Principal (initial amount), P = 3,200

#### Annual simple interest rate, R = 7%

#### From date: Oct 4, 2017

#### To date: Nov 4, 2017

#### Duration, T = 31 days

#### Commission fee (withdrawal or payment), F = 0.5%

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

## I = Simple interest:

#### I = (P × R × T) ÷ N =

#### (3,200 × 7% × 31) ÷ 365 =

#### (3,200 × 7 × 31) ÷ (365 × 100) =

#### 694,400 ÷ 36,500 ≈

#### 19.024657534247 ≈

#### 19.02

## B = Amount earned before deducting the

commission fee (withdrawal or payment):

#### B = P + I =

#### 3,200 + 19.024657534247 =

#### 3,219.024657534247 ≈

#### 3,219.02

## D = Amount earned after deducting the

commission fee (withdrawal or payment):

#### D = B - F =

#### B - F% × B =

#### (1 - F%) × B =

#### (1 - 0.5%) × 3,219.024657534247 =

#### 99.5% × 3,219.024657534247 ≈

#### 3,202.929534246576 ≈

#### 3,202.93

## Pr = Investment profit:

#### Pr = D - P =

#### 3,202.929534246576 - 3,200 =

#### 2.929534246576 ≈

#### 2.93