WAEC 2013 Mathematics · Question 19
A sales boy gave a change of N68 instead of N72. Calculate his percentage error
Options
- A.4%
- B.5%
- C.5%
- D.7%
Answer: B. 5%
Explanation written with AI and checked against the answer key
Analyze the question: The sales boy should have given N72 but gave N68. The percentage error is the error divided by the correct value, multiplied by 100. Concept: Percentage error = (Error ÷ Correct value) × 100% Solution: Error = 72 − 68 = N4 Percentage error = (4 ÷ 72) × 100% = (1 ÷ 18) × 100% = 100/18 % = 50/9 % = 5 5/9 % Check the options: 5 5/9% matches option B. (Option C would come from dividing by 68: 4/68 × 100 = 5 15/17%, but that uses the wrong value as the base. The error must be measured against the correct amount, N72.) Answer: B Tip: Percentage error always uses the correct (true) value as the denominator. In WASSCE, the options often include a "trap" answer from using the wrong base, like option C here.AI can make mistakes. Report anything that looks wrong.
Past questions © the examination body (JAMB/WAEC/NECO). DeeepSolve is not affiliated with them. Rights holders: see /copyright.