A week has 5 working days of 8 hours each. Regular pay is Rs. 2.40 per hour; overtime pay is Rs. 3.20 per hour. If a man earns Rs. 432 in 4 weeks, how many total hours did he work?

Given data

• Regular hours per week = 5 × 8 = 40 ⇒ in 4 weeks, up to 160 hours at regular rate.
• Rates: Rs. 2.40/hr (regular), Rs. 3.20/hr (overtime).
• Total pay = Rs. 432.

Concept / Approach

• Assume he works all 160 regular hours (common in such problems) and the rest, if any, is overtime.

Step-by-step calculation
Pay for 160 regular hours = 160 × 2.40 = Rs. 384Overtime pay needed = 432 − 384 = Rs. 48Overtime hours = 48 / 3.20 = 15 hoursTotal hours = 160 + 15 = 175

Verification
Wage = 160 × 2.40 + 15 × 3.20 = 384 + 48 = 432 ✔

Common pitfalls

• Calculating all hours at the regular rate or mixing rates; overtime applies beyond 40 hours/week.

Final Answer
175 hours