Question 1205528
Bod wants to put his footballs into boxes.
If he uses big boxes, he can put 7 footballs in each box with 4 footballs 
left over.
If he uses small boxes, he can put 5 footballs in each box with 4 footballs 
left over.
<pre>
What is the smallest number of footballs that Bob could own?

If he uses B big boxes, then he has 7B + 4 footballs.

If he uses S small boxes, then he has 5S + 4 footballs.
S small boxes.

Then he has 7B + 4 and also 5S + 4 footballs 

{{{7B + 4 = 5S +4}}}

{{{7B=5S}}}

{{{B/S=5/7}}}

The smallest number of footballs is when B and S are the smallest
they can be and be whole numbers.

That's when B=5 and S=7

So he has 7B+4 = 7(5)+4 = 35+4 = 39 footballs.
Checking:
It's also when he has 5S+4 = 5(7)+4 = 35+4 = 39 footballs.

Edwin</pre>