Say you have a1 as the buying price for the armchair and a2 as the selling price. The gross profit will be:
a2 - a1
Similarly, if you consider c1 the buying price of the coffee table and c2 its selling price, the gross profit from this transaction will be:
c2 - c1.
You are trying to establish some sort of relationship between the two profits.
1. tells you that a1 = 110% * c1 or that a1 = 1.1c1. This is insufficient to answer the question, however, since we don't have any info on a2 and c2.
2. means that a2 = 120% * c2 or that a2 = 1.2c2. This time around, no info about the buying prices.
Put both stmts together to get that:
a2 - a1 = 1.2c2 - 1.1c1 = 1.1c2 + 0.1c2 - 1.1c1 = 1.1(c2 - c1) + 0.1c2.
As you can see, you get that a2 - a1 = 1.1(c2 - c1) + 0.1c2. So, the gross profit from the armchair transaction is 1.1 times the gross profit from the coffee table transaction PLUS 0.1c2. Since we don't know c2, then we can't answer the question.
