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Question bank AMC12 1957

Exam papers

50 questions

Question 1

The number of distinct lines representing the altitudes, medians, and interior angle bisectors of a triangle that is isosceles, but not equilateral, is:
  1. $9$
  2. $7$
  3. $6$
  4. $5$
  5. $3$

Question 2

In the equation $2x^2-hx+2k=0,$ the sum of the roots is $4$ and the product of the roots is $-3.$ Then $h$ and $k$ have the values, respectively:
  1. $8$ and $-6$
  2. $4$ and $-3$
  3. $-3$ and $4$
  4. $-3$ and $8$
  5. $8$ and $-3$

Question 3

The simplest form of $1-\dfrac{1}{1+\dfrac{a}{1-a}}$ is:
  1. $a$ if $a\ne0$
  2. $1$
  3. $a$ if $a\ne-1$
  4. $1-a$ with no restriction on $a$
  5. $a$ if $a\ne1$

Question 4

The first step in finding the product $(3x+2)(x-5)$ by use of the distributive property in the form $a(b+c)=ab+ac$ is:
  1. $3x^2-13x-10$
  2. $3x(x-5)+2(x-5)$
  3. $(3x+2)x+(3x+2)(-5)$
  4. $3x^2-17x-10$
  5. $3x^2+2x-15x-10$

Question 5

Through the use of theorems on logarithms, $\log\dfrac ab+\log\dfrac bc+\log\dfrac cd-\log\dfrac{ay}{dx}$ can be reduced to:
  1. $\log\dfrac yx$
  2. $\log\dfrac xy$
  3. $1$
  4. $0$
  5. $\log\dfrac{a^2y}{d^2x}$

Question 6

An open box is constructed by starting with a rectangular sheet of metal $10$ in. by $14$ in. and cutting a square of side $x$ inches from each corner. The resulting projections are folded up and the seams welded. The volume of the resulting box is:
  1. $140x-48x^2+4x^3$
  2. $140x+48x^2+4x^3$
  3. $140x+24x^2+x^3$
  4. $140x-24x^2+x^3$
  5. none of these

Question 7

The area of a circle inscribed in an equilateral triangle is $48\pi.$ The perimeter of this triangle is:
  1. $72\sqrt3$
  2. $48\sqrt3$
  3. $36$
  4. $24$
  5. $72$

Question 8

The numbers $x,$ $y,$ $z$ are proportional to $2,$ $3,$ $5.$ The sum of $x,$ $y,$ and $z$ is $100.$ The number $y$ is given by the equation $y=ax-10.$ Then $a$ is:
  1. $2$
  2. $\dfrac23$
  3. $3$
  4. $\dfrac52$
  5. $4$

Question 9

The value of $x-y^{x-y}$ when $x=2$ and $y=-2$ is:
  1. $-18$
  2. $-14$
  3. $14$
  4. $18$
  5. $256$

Question 10

The graph of $y=2x^2+4x+3$ has its:
  1. lowest point at $(-1,9)$
  2. lowest point at $(1,1)$
  3. lowest point at $(-1,1)$
  4. highest point at $(-1,9)$
  5. highest point at $(-1,1)$

Question 11

The angle formed by the hands of a clock at $2:15$ is:
  1. $30^\circ$
  2. $27\frac12^\circ$
  3. $157\frac12^\circ$
  4. $172\frac12^\circ$
  5. none of these

Question 12

Comparing the numbers $10^{-49}$ and $2\cdot10^{-50},$ we may say:
  1. the first exceeds the second by $8\cdot10^{-1}$
  2. the first exceeds the second by $2\cdot10^{-1}$
  3. the first exceeds the second by
    $8\cdot10^{-50}$
  4. the second is five times the first
  5. the first exceeds the second by $5$

Question 13

A rational number between $\sqrt2$ and $\sqrt3$ is:
  1. $\dfrac{\sqrt2+\sqrt3}{2}$
  2. $\dfrac{\sqrt2\cdot\sqrt3}{2}$
  3. $1.5$
  4. $1.8$
  5. $1.4$

Question 14

If $y=\sqrt{x^2-2x+1}$ ${}+\sqrt{x^2+2x+1},$ then $y$ is:
  1. $2x$
  2. $2(x+1)$
  3. $0$
  4. $|x-1|+|x+1|$
  5. none of these

Question 15

The table below shows the distance $s$ in feet a ball rolls down an inclined plane in $t$ seconds.

$t$ $0$ $1$ $2$ $3$ $4$ $5$ $s$ $0$ $10$ $40$ $90$ $160$ $250$

The distance $s$ for $t=2.5$ is:
  1. $45$
  2. $62.5$
  3. $70$
  4. $75$
  5. $82.5$

Question 16

Goldfish are sold at $15$ cents each. The rectangular coordinate graph showing the cost of $1$ to $12$ goldfish is:
  1. a straight line segment
  2. a set of horizontal parallel line segments
  3. a set of vertical parallel line segments
  4. a finite set of distinct points
  5. a straight line

Question 17

A cube is made by soldering twelve $3$-inch lengths of wire properly at the vertices of the cube. If a fly alights at one of the vertices and then walks along the edges, the greatest distance it could travel before coming to any vertex a second time, without retracing any distance, is:
  1. $24$ in.
  2. $12$ in.
  3. $30$ in.
  4. $18$ in.
  5. $36$ in.

Question 18

Circle $O$ has diameters $\overline{AB}$ and $\overline{CD}$ perpendicular to each other. $\overline{AM}$ is any chord intersecting $\overline{CD}$ at $P.$ Then $AP\cdot AM$ is equal to:

Question illustration
  1. $AO\cdot OB$
  2. $AO\cdot AB$
  3. $CP\cdot CD$
  4. $CP\cdot PD$
  5. $CO\cdot OP$

Question 19

The base of the decimal number system is ten, meaning, for example, that $123=1\cdot10^2+2\cdot10+3.$ In the binary system, which has base two, the first five positive integers are $1,$ $10,$ $11,$ $100,$ $101.$ The numeral $10011$ in the binary system would then be written in the decimal system as:
  1. $19$
  2. $40$
  3. $10011$
  4. $11$
  5. $7$

Question 20

A man makes a trip by automobile at an average speed of $50$ mph. He returns over the same route at an average speed of $45$ mph. His average speed for the entire trip is:
  1. $47\frac7{19}$ mph
  2. $47\frac14$ mph
  3. $47\frac12$ mph
  4. $47\frac{11}{19}$ mph
  5. none of these