Using proportions, it is found that one mechanic could assemble 5 bicycles in 8 hours, and it would take 40 hours to assemble 25 bicycles.

The equation is: b = 0.625t.

What is a proportion?

A proportion is a fraction of a total amount, and the measures are related using a rule of three.

In this problem, two mechanics can assemble 10 bicycles in 8 hours. How many bicycles could one mechanic assemble in 8 hours? Hence the rule of three is given by:

2 mechanics - 10 bicycles.

1 mechanic - x bicycle.

Applying cross multiplication:

2x = 10 -> x = 5 bicycles in 8 hours.

Hence the equation for the number of bicycles in t hours of a single mechanic is given by:

b = 5/8t = 0.625t.

For 25 bicycles, we have that:

25 = 0.625t.

t = 25/0.625.

t = 40 hours.

More can be learned about proportions at