Add 20 numeric DynamoDB capacity practice questions

DynamoDB/Practice/Read and Write Units - Set 3.md

@@ -0,0 +1,96 @@
+# DynamoDB Read/Write Units — Numeric Practice, Set 3
+
+20 questions. Give a numeric answer for each, using `1 = <number>`, `2 = <number>`, and so on.
+
+## Assumptions
+
+- Assume provisioned capacity and steady workloads.
+- All item sizes are exact DynamoDB item sizes, including attribute names and values.
+- Each read accesses an individual item, not a Query or Scan. Transactional operations count individual items, not transaction API calls.
+- Normal writes are non-transactional. All writes create new items.
+- Ignore indexes, replication, retries, failed requests, burst capacity and partition limits.
+- Questions 1–14 ask for exact throughput requirements: fractional RCU answers are valid; do not round the final result to a whole number.
+- Questions 15–18 ask for the maximum number of individual item operations per second.
+- Questions 19–20 ask for whole-number provisioned capacity settings.
+
+## Questions
+
+### 1. You normally write six separate 1.8 KB items every second. How many WCUs are required?
+
+Answer: ______
+
+### 2. You normally write nine separate 0.7 KB items every second. How many WCUs are required?
+
+Answer: ______
+
+### 3. You normally write four separate 3.01 KB items every second. How many WCUs are required?
+
+Answer: ______
+
+### 4. You transactionally write three separate 2.01 KB items every second. How many WCUs are required?
+
+Answer: ______
+
+### 5. You transactionally write six separate 1 KB items every second. How many WCUs are required?
+
+Answer: ______
+
+### 6. You perform strongly consistent reads of five separate 5 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 7. You perform strongly consistent reads of three separate 12 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 8. You perform eventually consistent reads of nine separate 0.8 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 9. You perform eventually consistent reads of five separate 8.01 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 10. You perform eventually consistent reads of seven separate 8 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 11. You transactionally read five separate 4.01 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 12. You transactionally read three separate 11 KB items every second. How many RCUs of throughput are required?
+
+Answer: ______
+
+### 13. Each second, you normally write two 0.6 KB items and three 2.4 KB items to the same table. How many WCUs are required in total?
+
+Answer: ______
+
+### 14. Each second, you perform strongly consistent reads of two 5 KB items and eventually consistent reads of three 1 KB items from the same table. How many RCUs of throughput are required in total?
+
+Answer: ______
+
+### 15. You have 28 WCUs available. What is the maximum number of normal item writes per second you can sustain if each item is 3.2 KB?
+
+Answer: ______
+
+### 16. You have 30 WCUs available. What is the maximum number of transactional item writes per second you can sustain if each item is 2.2 KB?
+
+Answer: ______
+
+### 17. You have 15 RCUs available. What is the maximum number of eventually consistent item reads per second you can sustain if each item is 9 KB?
+
+Answer: ______
+
+### 18. You have 32 RCUs available. What is the maximum number of transactional item reads per second you can sustain if each item is 5 KB?
+
+Answer: ______
+
+### 19. You perform eventually consistent reads of eleven separate 3 KB items every second. What is the minimum WHOLE NUMBER of RCUs you must provision?
+
+Answer: ______
+
+### 20. You perform eventually consistent reads of five separate 12.01 KB items every second. What is the minimum WHOLE NUMBER of RCUs you must provision?
+
+Answer: ______