See the solutions to these problems just after the percentage calculator below.

Here are the solutions to the questions stated above:

Always use this formula to find a percentage:

^{%} / _{100} = ^{Part} / _{Whole} replace the given values:

^{40} / _{100} = ^{Part} / _{100000000}

Cross multiply:

40 x 100000000 = 100 x Part, or

4000000000 = 100 x Part

Now, divide by 100 and get the answer:

Part = ^{4000000000} / _{100} = 40000000

Use again the same percentage formula:

^{%} / _{100} = ^{Part} / _{Whole} replace the given values:

^{%} / _{100} = ^{40} / _{100000000}

Cross multiply:

% x 100000000 = 40 x 100

Divide by 100000000 and get the percentage:

% = ^{40 x 100} / _{100000000} = 4.0E-5%