[REOPENED] This question was closed as a duplicate. It's not a duplicate for two reasons. The major reason is that the question was not about how to solve the problem but about where the OP's own calculations went wrong. The minor reason is that the other question is more general and the generality requires more complicated answers that make it more difficult to find the error in the present simpler calculations. Please reopen.

[REOPENED] This question was closed as a duplicate. It's not a duplicate for two reasons. The major reason is that the question was not about how to solve the problem but about where the OP's own calculations went wrong. The minor reason is that the other question is more general and the generality requires more complicated answers that make it more difficult to find the error in the present simpler calculations. Please reopen.

This question was closed as a duplicate. It's not a duplicate for two reasons. The major reason is that the question was not about how to solve the problem but about where the OP's own calculations went wrong. The minor reason is that the other question is more general and the generality requires more complicated answers that make it more difficult to find the error in the present simpler calculations. Please reopen.

[REOPENED] This question was closed as a duplicate. It's not a duplicate for two reasons. The major reason is that the question was not about how to solve the problem but about where the OP's own calculations went wrong. The minor reason is that the other question is more general and the generality requires more complicated answers that make it more difficult to find the error in the present simpler calculations. Please reopen.