Difficulty: Easy
Correct Answer: 80
Explanation:
Introduction / Context:This is a linear equation problem involving separate contributions for working and non-working days. The worker receives a positive amount per working day and a deduction per absence, resulting in a relatively small net amount over a long period, which implies many absences.
Given Data / Assumptions:
Concept / Approach:Let w = number of working days and a = number of absences. Then w + a = 120. Net pay = 20w - 3a. Solve the simultaneous equations for a.
Step-by-Step Solution:
w + a = 120 ⇒ w = 120 - aNet pay: 20w - 3a = 56020(120 - a) - 3a = 5602400 - 20a - 3a = 5602400 - 23a = 560 ⇒ 23a = 1840 ⇒ a = 1840 / 23 = 80Verification / Alternative check:
w = 120 - 80 = 40Net = 20*40 - 3*80 = 800 - 240 = 560 (matches)Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
80
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