Question 1801
first, some definitions...

Let g be the amount invested in the greeting card business
Let b be the amount invested in the bicycle repair business.

So, what do we know?

Well, first the amounts invested added up to $2300, so {{{g+b=2300}}} in one equation.

What else? 

g made a profit of 14%. 14% means 14 OUT OF 100...PERCENT ie 14/100 ie 0.14. So the profit is 0.14g.

b made a loss of 6%. 6% means 6 OUT OF 100 ie 6/100 ie 0.06. So, the loss is 0.06b.

Together, these gave Chris a total return of $102, so

0.14g - 0.06b = 102.

Note the negative sign, because the bicycle place was a loss.

So, 2 equations...2 unknowns...simultaneous equation time. You solve those.

Answers...b=1100, g=1200. Hopefully, from my definitions, this will answer your question.

cheers
Jon.