# Python | Find the equivalent discount in successive discounts in percentages

You are given n successive discounts in percentages. Your task is to find the equivalent discount in percentage. Input will contain a list in which each element of the list will be discount in percentage that will be negative in sign.

**Examples:**

Input :a = [-10, -35, -60, -75]Output :-94.14Input :a = [-5, -20, -10.-23]Output :-49.08

SUCCESSIVE CHANGES = A + B + (A*B) / 100**How does this formula work?**

Let x be the initial value. After A% change, value of x becomes (x + x*A/100). After successive B% change, value of x becomes (x + x*A/100) + (x + x*A/100)*B/100. So increment in x’s value is x*(A + B + A*B/100)/100. In terms of percentage, we can say that the value is incremented by (A + B + A*B/100)%

**Approach:**

- Simply, apply sucessive change formula between arr[0] and arr[1] and store the result in result variable.
- Now, calculate successive change between result and arr[2] using the above formula and store the result in result variable and so on.

**Code: Python program for finding the equivalent discount in successive discounts in percentages.**

`# Function to find the equivalent discount in ` `# successive discounts in percentages` `def` `equivalentdis(a):` ` ` `if` `(` `len` `(a)` `=` `=` `1` `):` ` ` `return` `(a[` `0` `])` ` ` `else` `:` ` ` `# succesive change from two = a[0] + a[1]+ (a[0]*a[1])/100` ` ` `change ` `=` `(a[` `0` `] ` `+` `a[` `1` `]` `+` `(a[` `0` `]` `*` `a[` `1` `])` `/` `100` `)` ` ` `for` `i ` `in` `range` `(` `2` `, ` `len` `(a)): ` ` ` `# iterating a[0] + a[1]+ (a[0]*a[1])/100 ` ` ` `# len(a)-2 times` ` ` `change ` `=` `(change ` `+` `a[i]` `+` `(change ` `*` `a[i]) ` `/` `100` `)` ` ` `return` `change; ` `# Driver code` `print` `(equivalentdis([` `-` `10` `, ` `-` `20` `, ` `-` `30` `, ` `-` `40` `]))` ` ` |

**Output :**

-69.75999999999999

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