Question 1183595
<br>
Logically, if the sum of two whole numbers is 45, then one of them is even and the other is odd.<br>
If two whole numbers are one even and the other odd, then their difference is an odd number.<br>
Since the problem requires that the difference between the two numbers be less than 10, the difference can be either 1, 3, 5, 7, or 9.<br>
So there are 5 pairs of whole numbers that satisfy the conditions of the problem.<br>
ANSWER: 5<br>
Algebraically....<br>
Let the larger number be x and the smaller be y.<br>
{{{x+y=45}}}
{{{x-y<10}}}<br>
Solve the first equation for y:
{{{y=45-x}}}<br>
Substitute in the inequality:
{{{x-(45-x)<10}}}
{{{2x-45<10}}}
{{{2x<55}}}
{{{x<27.5}}}<br>
The larger number has to be less than 27.5, so the largest it can be is 27.<br>
That's as far as the algebraic solution gets you; you still have to do some logical reasoning to find the answer to the problem.<br>
Since x is the larger of the two numbers, it has to be greater than 45/2=22.5, so the smallest it can be is 23.<br>
That means the larger number can be any whole number between 23 and 27, inclusive; that is 5 numbers.<br>