1980 年

The figure above shows the graph of $y=ax^2+bx+c$. Determine whether $a$ and $c$ are positive or negative.

$\$P$ amounts to $\$Q$ in $n$ years at simple interest. The rate per annum is

If $0<x<1$, which of $x$, $x^2$, $\dfrac{1}{x}$, $\sqrt{x}$ is the smallest? Which is the largest?

The Highest Common Factor of two unequal positive integers $a$ and $b$ is $8$. Which of the following must be true? I. The difference between $a$ and $b$ is divisible by $8$ II. $(a+b)$ is divisible by $16$ III. $ab$ is divisible by $64$

$x$, $y$ and $z$ are three consecutive positive integers. Which of the following is true?

If $x^2-kx+9\ge 0$ for all real values of $x$, what is the value of $k$?

If $x$ and $y$ are real numbers, what is the minimum value of the expression $(x+y)^2-1$?

In the figure, the areas of the surfaces $A$, $B$, $C$ of the cuboid are $10\text{ cm}^2$, $14\text{ cm}^2$ and $35\text{ cm}^2$ respectively. What is the volume of the cuboid?

$x$ is a positive integer such that $x^2+2x+7$ is even. What are the possible values of $x$?

The perimeter of a sector is $16$ and its angle is $2$ radians. What is the area of the sector?