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SEAMO 2022 — Paper D — Grade 7–8

Question 1

Compare (i) $2^{329}$ and (ii) $5^{141}$. Which statement is true?
  1. (i) > (ii)
  2. (i) = (ii)
  3. (i) < (ii)
  4. Both A and B
  5. Both B and C

Question 2

A bell chimes whenever the hands of a standard twelve-hour clock form a $180^\circ$ angle. How many chimes occur from one midnight to the next?
  1. $20$
  2. $21$
  3. $22$
  4. $23$
  5. $24$

Question 3

If $7.03^3=347.428927$, find $0.703^3$.
  1. $0.034728927$
  2. $0.34728927$
  3. $3.47289727$
  4. $0.0034728927$
  5. $0.00034728927$

Question 4

Integers $m\gt n$ satisfy $m+n=20,m^2+n^2=328$. Find $m^2-n^2$.
  1. $280$
  2. $292$
  3. $300$
  4. $320$
  5. $340$

Question 5

Evaluate $\sum_{k=1}^{2021}\frac{2022}{k(k+1)}$.
  1. $2020$
  2. $2021$
  3. $2022$
  4. $2023$
  5. $2024$

Question 6

Find the smallest positive integer k such that $2^{91}+k$ is divisible by one hundred twenty-seven.
  1. $122$
  2. $123$
  3. $124$
  4. $125$
  5. $126$

Question 7

The six-digit integer $\overline{abcdef}$ satisfies $\overline{fabcde}=5\overline{abcdef}$. Find a+b+c+d+e+f.
  1. $25$
  2. $26$
  3. $27$
  4. $28$
  5. $30$

Question 8

A sphere’s radius increases five percent. Find its volume’s percentage increase, to one decimal place. Use $V=4\pi r^3/3$.
  1. $11.5\%$
  2. $12.8\%$
  3. $15\%$
  4. $15.8\%$
  5. $4\%$

Question 9

Two independent football matches each have equally likely win, draw and loss. The probability of at least one draw is m/n. Find m+n.
  1. $13$
  2. $14$
  3. $15$
  4. $16$
  5. $17$

Question 10

Positive integers x,y are less than ten and satisfy $2^x9^y=\overline{2x9y}$. Find x+y.
  1. $6$
  2. $7$
  3. $8$
  4. $9$
  5. $10$

Question 11

Solve $\log_x(2x^2-7x+12)=2$.
  1. $0,1$
  2. $1$
  3. $-2,3$
  4. $2,3$
  5. $3,4$

Question 12

Solve $1+\sin\theta-2\cos^2\theta=0$ for $0^\circ\le\theta\le90^\circ$.
  1. $10^\circ$
  2. $20^\circ$
  3. $30^\circ$
  4. $45^\circ$
  5. $60^\circ$

Question 13

Find the last two digits of $9^{2022}$.
  1. $21$
  2. $81$
  3. $09$
  4. $61$
  5. $01$

Question 14

In the cryptarithm $MATH+MATH=HABIT$, different letters represent distinct digits. Find B.

Question illustration
  1. $0$
  2. $1$
  3. $2$
  4. $3$
  5. $4$

Question 15

If $x^2-10x+1=0$, find $x^4+x^{-4}$.
  1. $1112$
  2. $3345$
  3. $7963$
  4. $9602$
  5. $9935$

Question 16

Evaluate $\frac{16}{345678^2-345674\times345682}$.
  1. $1$
  2. $2$
  3. $3$
  4. $16$
  5. $345678$

Question 17

In triangle ABC, $AB=AC$. D is on AC and E on AB, with $AD=DE=BE$ and $BD=BC$. Find angle A.

Question illustration
  1. $30^\circ$
  2. $34^\circ$
  3. $37^\circ$
  4. $41^\circ$
  5. $45^\circ$

Question 18

Given $a=\sqrt6-2,b=2\sqrt2-\sqrt6$, which statement is true?
  1. $a\gt b$
  2. $a=b$
  3. $a\lt b$
  4. $b=\sqrt{2a}$
  5. $a=\sqrt{2b}$

Question 19

Count integers n from one through $2022$ for which $1^n+2^n+3^n+4^n+5^n$ is divisible by five.
  1. $1503$
  2. $1507$
  3. $1508$
  4. $1510$
  5. $1517$

Question 20

Which expression is greatest?
  1. $\sqrt8+\sqrt8$
  2. $\sqrt9+\sqrt7$
  3. $\sqrt{10}+\sqrt6$
  4. $\sqrt{11}+\sqrt5$
  5. $\sqrt{12}+\sqrt4$