Math CentralQuandaries & Queries

Question from Samima:

Two numbers have a difference of 0.85 and the sum 1.What are the numbers?

Hi Samima,

The subject line of your email was Algebra so let's do it algebraically.

Suppose the two numbers are $a$ and $b$ where $a$ is the larger. The sum of the two numbers is 1 and the difference is 0.85 so you know that

\[a + b = 1 \mbox{ and } a - b = 0.85.\]

Adding these two equations gives

\[a + b + a - b = 1 + 0.85 \mbox{ or } 2a = 1.85.\]

Solve for $a$ and $b.$ Once you have found $a$ and $b,$ verify that they are correct.


About Math Central
* Registered trade mark of Imperial Oil Limited. Used under license.


Math Central is supported by the University of Regina and the Imperial Oil Foundation.
Quandaries & Queries page Home page University of Regina Imperial Oil Foundation