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AMO 2022 – Primary 5 (Grade 5)

Question 1

Three-eighths of Sarah’s stickers are flowers. Two-fifths of the flower stickers are red roses. What fraction of all her stickers are not red roses?

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  1. $\frac3{20}$
  2. $\frac18$
  3. $\frac35$
  4. $\frac58$
  5. $\frac{17}{20}$

Question 2

A bottle of 2% milk says it has 37% less fat than regular milk. Approximately what percentage of regular milk is milkfat?

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  1. 3.2%
  2. 6.8%
  3. 39%
  4. 18.5%
  5. 1.8%

Question 3

Round the following value to the nearest ten-thousandth:

$$5\frac 34+0.0000001+10\frac{12}{14}+\frac{234}{100000}$$

Original choices: A.16.3693; B.16.5672; C.16.6094; D.16.7431; E.16.609. None is correct; this adapted question asks for a numeric answer.

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Question 4

If the dot pattern continues, how many dots are at step 98?

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  1. 9999
  2. 9801
  3. 10000
  4. 9898
  5. 9595

Question 5

Helen has a rectangular red cloth measuring 8 cm by 15 cm. She cuts out a triangular flag of the largest possible area, then uses all the remaining cloth to make two equal-area red flags. What is the area of each smaller flag in square centimetres?

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  1. 30
  2. 60
  3. 90
  4. 120
  5. 150

Question 6

Triangle ABC has $AB=AC$ and $\angle CAB=40^\circ$. Extend AB beyond B to D so that $\angle ACD=90^\circ$. Find $\angle BCD$ in degrees. Original choices: A.30°; B.40°; C.50°; D.60°; E.70°. None is correct for the angle asked; enter a numeric answer.

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Question 7

Four classroom lights work independently. Each has a 90% probability of still working after 1000 hours. What is the probability that at least one still works then?

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  1. 90%
  2. 99.99%
  3. 98.88%
  4. 95.00%
  5. 89.10%

Question 8

If positive integers R and S are divisible by 9 and 8 respectively, what is the minimum number of factors greater than 1 of RS?

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  1. 8
  2. 11
  3. 13
  4. 17
  5. 18

Question 9

Mrs. Jones’s 25 students had a test average of 89. Tony says that if his score had been 96, the class average would have been 90. What was his actual score?

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  1. 81
  2. 65
  3. 71
  4. 75
  5. 55