Mixed Deck — All AMC12 Topics Flashcards
100 cards from real AMC12 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 20 Mixed Deck — All AMC12 Topics flashcards as text
In the Fibonacci sequence 1, 1, 2, 3, 5, 8, ..., what is the 8th term?
Answer: 21
Continuing the Fibonacci sequence: the 8th term is 21.
If z = cos(π/6) + i·sin(π/6), what is z + z̄ (z plus its complex conjugate)?
Answer: √3
z = √3/2 + i/2 and z̄ = √3/2 − i/2, so z + z̄ = √3 (the imaginary parts cancel).
How many solutions does sin(x) = sqrt(3)/2 have in [0, 2pi)?
Answer: 2
sin(x)=sqrt(3)/2 at x=pi/3 and x=2pi/3, giving 2 solutions.
A committee of 3 is chosen from 7 people. How many ways can this be done?
Answer: 35
C(7, 3) = 7!/(3! × 4!) = 35.
If log(xy)=5 and log(x/y)=1, what is log x?
Answer: 3
Adding the two equations gives 2log(x)=6, so log(x)=3.
What is the product of the three terms of the geometric sequence 2, 6, 18?
Answer: 216
2 × 6 × 18 = 216; note 6 = ∛216, which confirms the middle term property.
What is C(8, 3)?
Answer: 56
C(8, 3) = 8 × 7 × 6 / (3 × 2 × 1) = 336/6 = 56.
What is the 10th term of the arithmetic sequence 3, 7, 11, 15, ...?
Answer: 39
The common difference is 4, so a₁₀ = 3 + 9 × 4 = 3 + 36 = 39.
What is cos(π)?
Answer: −1
cos(π) = −1 since π radians corresponds to 180°.
A triangle has vertices (0,0), (4,0), and (0,3). What is its area?
Answer: 6
Area=(1/2)*base*height=(1/2)(4)(3)=6.
What is the arithmetic mean of 2, 5, 8, 11, 14?
Answer: 8
The sum is 40, divided by 5 gives mean = 8; it also equals the middle term of this AP.
In a group of 30 people, the probability that at least two share a birthday is approximately:
Answer: Greater than 70%
The birthday problem gives approximately 70.6% for 30 people.
What is 0! (zero factorial)?
Answer: 1
By convention (and the gamma function), 0! = 1.
If P(A)=0.4 and P(B)=0.5 and A and B are independent, what is P(A and B)?
Answer: 0.2
For independent events, P(A and B)=P(A)*P(B)=0.4*0.5=0.2.
What is the sum from k=1 to 100 of (1/k - 1/(k+1))?
Answer: 100/101
This telescoping series sums to 1-1/101=100/101.
What is the 7th term of a geometric sequence with first term 2 and ratio 3?
Answer: 1458
a_7=2*3^6=2*729=1458.
What is the real part of (3 + 4i) / (1 + 2i)?
Answer: 11/5
Multiply numerator and denominator by the conjugate (1−2i): (3+4i)(1−2i)/5 = (11−2i)/5, giving real part 11/5.
A fair die is rolled. What is the probability of getting a number greater than 4?
Answer: 1/3
The favorable outcomes are {5, 6}, so probability = 2/6 = 1/3.
What is the sum to infinity of 1 + 1/2 + 1/4 + ...?
Answer: 2
S=a/(1-r)=1/(1-1/2)=2.
What is the probability of rolling a sum of 7 with two standard dice?
Answer: 1/6
The 6 outcomes summing to 7 give P=6/36=1/6.