Question 770062
<pre>
25 must be increased by 15 to become 40.
Ratio of increase means "by what fraction has 25 increased to become 40"? So we 
need to express the increase (15) as a part of 25.
15 expressed as a part of 25 = 15/25 = 0.6 = 60%
So the ratio of increase is 0.6
</pre>