Math Help - Percentages Problem

I have a problem I can't solve as below.

If someone wanted to be paid a nett figure of £912.00 but has a 10% subcontractor allowance deducted but they themselves have a 4.5% surcharge what is the original figure that I would need to pay them? I really need to know a formula to get to this original figure. See example below;

Nett Figure = £912.00

Therefore we pay £969.70 (Derived from guess work). This is the figure I need to know
Less 10% (£96.97) = £872.73
Plus 4.5% (39.27) = £912.00 Nett

Thanks.

Originally Posted by hrg340821

I have a problem I can't solve as below.

If someone wanted to be paid a nett figure of £912.00 but has a 10% subcontractor allowance deducted but they themselves have a 4.5% surcharge what is the original figure that I would need to pay them? I really need to know a formula to get to this original figure. See example below;

Nett Figure = £912.00

Therefore we pay £969.70 (Derived from guess work). This is the figure I need to know
Less 10% (£96.97) = £872.73
Plus 4.5% (39.27) = £912.00 Nett

Thanks.

(x - 10% of x) + 4.5% of (x - 10% of x) = 912

=> (9/10)x + (9/200)(9/10)x = 912

=> x = 969.70.

Note:
10% --> 10/100 = 1/10
4.5% --> 4.5/100 = 9/200

Originally Posted by mr fantastic

(x - 10% of x) + 4.5% of (x - 10% of x) = 912

=> (9/10)x + (9/200)(9/10)x = 912

=> x = 969.70.

Note:
10% --> 10/100 = 1/10
4.5% --> 4.5/100 = 9/200

Is there any chance you could write this out a little clearer and easier for a non maths person like me! I need to use this withing a spreadsheet, if you could possibly put in a spreadsheet and email me at (Moderator Edit: email deleted) that would be great!!!!

Originally Posted by hrg340821

Is there any chance you could write this out a little clearer and easier for a non maths person like me! I need to use this withing a spreadsheet, if you could possibly put in a spreadsheet and email me at (Moderator Edit: email deleted) that would be great!!!!

No, that's not how things work.

If you have a question about the calculation, please be specific. Otherwise, I've shown you how the calculation is done. The rest is up to you.

So the way I work it from what you have said is;

(0.9)x + (0.045)(0.9)x = 912
Therefore
(0.9)x + (0.0405)x = 912
Therefore
2x=912/(0.9-0.0405)
Therefore
2x=912/0.8595
Therefore
2x=1061.082024
Therefore
x=1061.082024/2
Therefore
x=530.54

Which is wrong. Where am I going wrong? Its been a few years since I did Maths and need help!

Originally Posted by hrg340821

So the way I work it from what you have said is;

(0.9)x + (0.045)(0.9)x = 912
Therefore
(0.9)x + (0.0405)x = 912
Therefore
2x=912/(0.9-0.0405)
Therefore
2x=912/0.8595
Therefore
2x=1061.082024
Therefore
x=1061.082024/2
Therefore
x=530.54

Which is wrong. Where am I going wrong? Its been a few years since I did Maths and need help!

Everything in red is wrong and I have no idea how you came up with it.

(0.9)x + (0.0405)x = 912

=> 0.9405x = 912

=> x = 969.70