Crazy Bird Academic Arithmetic Blocked In

Academic Arithmetic is a weekly puzzle in Professor Layton and the Unwound Future.

Puzzle[edit | edit source]

An exclusive three-year private school has admitted only 100 new students a year since its inception three years ago.

Starting at year four, the school plans to admit 10 more new students each year than it did the previous year.

In what year of operation will the school's population first exceed 400 students?

Hints[edit | edit source]

Click a Tab to reveal the Hint.

When calculating the school's total enrollment, think in three-year chunks.

In its fourth year, the school will have an additional 10 students overall than the previous year. The fifth year will have 20 more than that, and the sixth will have another 30.

Each year thereafter, the enrollment will grow by 30 students a year.

Solution[edit | edit source]

Incorrect[edit | edit source]

Too bad!

Think about it carefully, and try again.

Correct[edit | edit source]

A plus!

The school's population will exceed 400 students in year eight.

Every year from year four onward, the number of new students will increase by 10, but the students who started three years earlier will graduate and leave. In year four, five and six, the population will increase by 10, 20, and then 30 students a year. After that, the population will increase steadily by 30 students a year.


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