







I was paid 67% of the total owed 
20160125 

From Julie: I was paid $27000. This is 67% of the Total Owed. The Total Owed is unknown. How do I calculate the amount of the Total Owed? Answered by Penny Nom. 





A reversed curved on a railroad track 
20140619 

From cherrielyn: Assuming that earth is a sphere of radius 6380 km,
what is the difference in the latitudes of two cities 270 miles apart
positioned on the same meridian?
Thank you in advanced po! :) Answered by Penny Nom. 





How do i reverse this formula? 
20130420 

From MK: I have 22,000,000 worth of gold and wants to want to resell the gold back with a profit.
Each transaction of gold will have a transaction fee of 15%, so if i resell the gold back at 22,000,000, I will only get back 18,700,000 after 15% transaction cut.
The current formula is X15%X = Y where X = 22,000,000 and Y = 18,700,000
Will u be able to come up with a new formula if we don't know the value of X but we know the value of Y
Something like this X15%X = 22,000,000.
How do i reverse this formula to find the value of X
Thanks Answered by Penny Nom. 





Reversing the digits 
20110208 

From rejie: if the digits are reverse , the number is 9 less than the original number.what is the equation? Answered by Penny Nom. 





A reverse PST calculation 
20100923 

From Manning: Hi, I'm a manufacturing contractor in Saskatoon. The way to calculate PST for us is using total contract amount x 70% then 5%.
For example, contract amount of $100 x 70% x 5% = $3.5 (PST). The subtotal is using contract amount + PST.
$100 + $3.50 = $103.50.
If you only know the subtotal is $103.50 including PST, how do you reverse calculation to get the contract amount?
Thank you very much for your help. Answered by Harley Weston. 





Sales taxes in Quebec 
20100428 

From carole: I work at a company where we use transport companies and we often get credits
on their invoices. I need to know how to subtract the sales taxes from these credit amounts.
(5% TPS and 7.5% TVQ).
Is the equation: Amount / 1.05 = then this amount / by 1.075=? Answered by Penny Nom. 





Reverse percentage 
20060419 

From Mike: How would I calculate a reverse percentage?
Let me give you an example. I have two values that calculate to a success rate of 93.32. Total=1546051 Failures=103302. (1546051103302)/1546051=93.32% success.
Now how much would I need to increase the total value to get the success up to 95%? Answered by Stephen La Rocque. 





Reverse pecentage 
20050301 

From Nathan: Question for you. If I have spent $10.00, what is the mathamatical equation to
figure out what the G.S.T (7%) was?
Also if I were to spend $80.00 on a hotel, and I would like to know how much
G.S.T (7%) and how much provincial tax (6%) I spent how would I go about this.
Answered by Penny Nom. 





Why do you flip the inequality sign? 
20011026 

From Sean: I have a question about an inequality problem. Here it is: Solve and graph 5  3x => 17. (=> is greater than or equal). Please tell me why you flip the inequality sign when divinding by a negative number. Answered by Penny Nom. 





Reversing the direction of an inequality. 
19990306 

From Mallory White: If the Problem was 4a plus 5 is less than or equal to 14, why would you change the sign to greater than or equal to? Answered by Jack LeSage and Harley Weston. 

