Answer:
Mr. Porter's claim was not correct and it will be a 21% increment.
Step-by-step explanation:
The value of the house when Mr. Porter bought the house was d.
The present value of the house is given by d + 0.21d = 1.21d.
Hence, the increase in the value of the house is 0.21 d and the final value of the house is 1.21d.
So, if Mr. Porter claims that the value of his house has increased by 121%, then his claim is wrong. The increase in value is only by 0.21d i.e. by 21% and after this increment, the value becomes 1.21d i.e. 121%.
Therefore, his claim is not correct and it will be a 21% increment. (Answer)
