Time, Work and interest mixed

 Time and Work

Kezang can complete a job in 12 days, and Ugyen in 18 days. They work together for 4 days. How much work is left?

Solution:
Kezang = 1/12, Ugyen = 1/18
Together per day = (1/12 + 1/18) = 5/36
In 4 days: 4 × 5/36 = 20/36 = 5/9
Work left = 1 − 5/9 = 4/9

✅ Answer: 4/9 of the work remains

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Simple Interest

Sonam deposited Nu. 12,000 at 6% simple interest for 3 years. What is the total interest?

Solution:
SI = (P × R × T) / 100 = (12000×6×3)/100 = Nu. 2,160

✅ Answer: Nu. 2,160

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Compound Interest

Jigme invested Nu. 5,000 at 10% compound interest annually for 2 years. What is the compound interest?

Solution:
Amount = P(1 + R/100)^T = 5000(1.1)^2 = 5000 × 1.21 = Nu. 6,050
CI = 6050 − 5000 = Nu. 1,050

✅ Answer: Nu. 1,050

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Profit and Loss

Dema bought oranges for Nu. 1,200 and sold them for Nu. 1,560. What was her profit percentage?

Solution:
Profit = 1560 − 1200 = 360
Profit% = (360/1200) × 100 = 30%

✅ Answer: 30% profit

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Partnership

Kinley and Karma invested Nu. 10,000 and Nu. 15,000 respectively in a business. After 8 months, they made a profit of Nu. 9,200. What is Kinley’s share?

Solution:
Ratio = 10,000×8 : 15,000×8 = 10:15 = 2:3
Kinley’s share = 2/5 × 9200 = Nu. 3,680

✅ Answer: Nu. 3,680

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Percentage

Pelden's salary increased from Nu. 12,000 to Nu. 14,400. What is the percentage increase?

Solution:
Increase = 2400 → % = (2400/12000)×100 = 20%

✅ Answer: 20% increase