9(3+5) is equivalent because factoring a 9 out of both 27 and 45 leaves us with 9(3+5).
I take it that only 7 stamps are misplaced and that we are asked for the total value of the stamps including those which have been misplaced.
If each is worth $0.15 then, the total worth of 7 stamps is $1.05. Then, we add this value to the value of his remaining stamps, $5.55, the answer would be $6.60.
