Đề thi Olympic Tiếng Anh lớp 11 vòng 20 năm 2013 - 2014

What is the ones digit of 7²⁰¹¹?

Jane is keeping a journal in a notebook. She numbers each page of the journal by hand. When she finishes numbering the pages she realizes it took her twice as many digits as the number of the last page to do so. How many pages does the journal contain?

How many points (x, y) with integer coordinates lie inside or along the boundary of the circle of radius 5 centered at (0, 0)?

If f(x) = 3x - 7, then f^-1(f^-1(-1)) is which of the following?

Suppose that the number 11A1B is divisible by 3, where A and B represent distinct digits from {0, 1, 2,..., 9}. How many values of A + B are possible?

Six people are sitting in a room. When an 80-year old man enters the room, the average age of the people in the room doubles. What was the average age of the six people originally sitting in the room?

Working together, Gary and his dad were able to paint their living room in h hours. From experience, Gary's dad knows that it takes him d hours to do this task alone. How long would it take Gary to paint the living room alone?

If f(x) = x² + 1 and g(x) = x³, which of the statements above is/are true?

If -3x2 + kx + 18 has two integer roots that are five units apart, then k could be which of the following?

A Kakuro puzzle asks the solver to enter a digit from 1 to 9 inclusive in each blank so that the sum of the number in each row or column matches the clue and so that no digit is repeated in the sum. For example, the sum for a clue 6 with two blanks could only be 6 = 1 + 5 or 6 = 2 + 4. Which number(s) can be a clue in the position marked x?