Explanation

Use the work formula: 

Workers × Days × Hours per day / Units = constant

Case 1: 

30 workers, 20 days, 8 hours/day, 3000 units

Case 2: 

32 workers, D days, 10 hours/day, 2000 units

So,

(30 × 20 × 8) / 3000 = (32 × D × 10) / 2000

4800 / 3000 = 320D / 2000

1.6 = 0.16D

D = 1.6 / 0.16 = 10

Last verified on 05-08-2026

Explanation

Total work = Number of labourers x Total days  

Total work = 20 x 8 = 160 units  

Work done in first 4 days = 20 labourers x 4 days  

Work done = 80 units  

Fraction of work completed = Work done / Total work  

= 80 / 160  

= 1 / 2  

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Explanation

Work (in worker-days) = 15 × 12 = 180

Days for 10 workers = 180 ÷ 10 = 18 days.

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Explanation

Total number of students = 45  

Ali's rank from the top = 12th  

To find rank from the bottom we use this formula:  

Rank from bottom = Total students - Rank from top + 1  

Put the values:  

Rank from bottom = 45 - 12 + 1  

Rank from bottom = 33 + 1  

Rank from bottom = 34  

Last verified on 01-08-2026

Explanation

Let sister’s age = x, Sara’s age = 2x

x + 2x = 36 → 3x = 36 → x = 12 → Sara’s age = 24 years.

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