Q6. An article is sold at a loss of 10%. Had it been sold for ₹60 more, there would have been a gain of 10%. Find the cost price (in ₹).
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Answer: C. 300
10% + 10% = 20% of CP = ₹60, so CP = 60 × 100/20 = ₹300.
Profit and Loss · hard
Q7. The population of a town is 65000. It increases by 20% every year. What will the population be after 3 years?
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Answer: A. 112320
65000 × (120/100)^3 = 112320.
Percentage · medium
Q8. Find the compound interest on ₹40000 for 1 year at 20% per annum, compounded half-yearly (in ₹).
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Answer: C. 8400
Rate = 10% per half-year for 2 periods. A = 40000 × (110/100)² = ₹48400; CI = ₹8400.
Compound Interest · hard
Q9. Two cities are 450 km apart. Two cars start at the same time from the two cities towards each other at 40 km/h and 20 km/h. After how many hours will they meet?
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Answer: D. 7.5 hours
Time = 450/(40 + 20) = 7.5 hours.
Speed, Time and Distance · medium
Q10. A batsman has an average of 55 runs after 13 innings. How many runs must he score in the next innings to raise his average by 4?
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Answer: C. 111
New total = 14 × 59 = 826; old total = 13 × 55 = 715. Runs = 111.
Average · hard
Q11. A boat goes downstream at 11 km/h and upstream at 1 km/h. What is the speed of the stream?
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Answer: D. 5 km/h
(11 − 1)/2 = 5 km/h.
Boats and Streams · medium
Q12. What is the difference between compound interest and simple interest on ₹9000 for 2 years at 20% per annum (in ₹)?
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Answer: D. 360
CI − SI = 9000 × (20/100)² = ₹360.
Compound Interest · hard
Q13. The present ages of A and B are in the ratio 2:9. After 12 years, their ages will be in the ratio 8:15. What is A's present age?
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Answer: C. 4 years
15(2x + 12) = 8(9x + 12) ⇒ x = 2. A's age = 2 × 2 = 4 years.
Problems on Ages · hard
Q14. A, B and C can do a work alone in 6, 12 and 12 days respectively. How many days will they take working together?
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Answer: D. 3 days
1/6 + 1/12 + 1/12 = 1/3. So they need 3 days.
Time and Work · medium
Q15. The average of 5 consecutive even numbers is 42. What is the largest of these numbers?
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Answer: C. 46
The middle (3th) number is 42. The largest is 2 steps of 2 above it: 42 + 4 = 46.
Average · medium
Q16. If tan θ = 9/40 (θ acute), find sec θ.
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Answer: B. 41/40
Hypotenuse = √(9² + 40²) = 41. sec θ = 41/40.
Trigonometry · hard
Q17. Find the mean proportional between 384 and 288.
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Answer: C. 48
√(384 × 288) = √110592 = 48.
Ratio and Proportion · medium
Q18. Two trains of lengths 250 m and 110 m run in the same direction at 36 km/h and 54 km/h. How long will they take to cross each other completely?
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Answer: A. 72 seconds
Relative speed = 18 km/h = 5 m/s. Time = (250 + 110)/5 = 72 s.
Speed, Time and Distance · hard
Q19. A batsman has an average of 43 runs after 20 innings. How many runs must he score in the next innings to raise his average by 3?
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Answer: A. 106
New total = 21 × 46 = 966; old total = 20 × 43 = 860. Runs = 106.
Average · hard
Q20. A pipe can fill a tank in 4 hours, while a leak can empty the full tank in 12 hours. If both are open, how long will it take to fill the tank?
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Answer: C. 6 hours
Net filled per hour = 1/4 − 1/12 = 8/48. Time = 48/8 = 6 hours.
Pipes and Cisterns · hard
Q21. Two cities are 270 km apart. Two cars start at the same time from the two cities towards each other at 24 km/h and 36 km/h. After how many hours will they meet?
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Answer: A. 4.5 hours
Time = 270/(24 + 36) = 4.5 hours.
Speed, Time and Distance · medium
Q22. Find the volume of a cone with base radius 7 cm and height 20 cm. (Take π = 22/7)
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Answer: C. 1026 2/3 cm³
V = 1/3 × 22/7 × 7² × 20 = 1026 2/3 cm³.
Mensuration · hard
Q23. The speed of a boat in still water is 10 km/h and the speed of the stream is 2 km/h. How long will the boat take to go 32 km upstream?
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Answer: A. 4 hours
Upstream speed = 10 − 2 = 8 km/h. Time = 32/8 = 4 hours.
Boats and Streams · medium
Q24. How many factors (divisors) does 200 have?
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Answer: D. 12
200 = 2^3 × 5^2; number of factors = 4 × 3 = 12.
Number System · hard
Q25. An article is sold at a loss of 4%. Had it been sold for ₹290 more, there would have been a gain of 6%. Find the cost price (in ₹).
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Answer: D. 2900
4% + 6% = 10% of CP = ₹290, so CP = 290 × 100/10 = ₹2900.