CMA Foundation · Fundamentals of Business Mathematics and Statistics · Arithmetic Progression and Geometric Progression
A company's cost of drilling a well is Rs 5,000 for the first metre and rises by Rs 250 for each subsequent metre. What is the total cost of drilling 20 metres?
The total cost is Rs 1,47,500, found as the sum of an AP with first term 5,000, difference 250 and 20 terms: 10 times 14,750.
- ARs 1,47,500Correct
- BRs 1,00,000
- CRs 1,50,000
- DRs 1,47,000
Explanation
AP with a=5,000, d=250, n=20. Sum = 20/2 x [10,000 + 19x250] = 10 x 14,750 = Rs 1,47,500. Using n=20 with last term 5,000+20x250 gives an error giving Rs 1,50,000.
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