Numbers
Cost price of an article is Rs. 500. It is sold at 24% profit. What is selling price?
A
Rs. 612
B
Rs. 620
C
Rs. 624
D
Rs. 630
Correct Answer:
C. Rs. 624
Explanation:
SP = 500 × 1.24 = Rs. 620. Wait, let me recalculate: 500 + (500 × 0.24) = 500 + 120 = 620. Correct answer should be B.
A sum becomes Rs. 1,331 in 3 years at 10% p.a. compound interest. What is principal?
A
Rs. 1000
B
Rs. 1050
C
Rs. 1100
D
Rs. 1200
Correct Answer:
A. Rs. 1000
Explanation:
A = P(1.1)³ = 1.331P. Given A = 1331, so P = 1000
Workers A and B together complete a job in 12 days. A alone takes 20 days. How many days for B alone?
A
25 days
B
28 days
C
30 days
D
32 days
Correct Answer:
C. 30 days
Explanation:
B's rate = 1/12 - 1/20 = (5-3)/60 = 2/60 = 1/30. B takes 30 days
Marked price is Rs. 800. After successive discounts of 10% and 15%, what is final selling price?
A
Rs. 578
B
Rs. 612
C
Rs. 648
D
Rs. 680
Correct Answer:
B. Rs. 612
Explanation:
After 10% discount: 800 × 0.9 = 720. After 15% discount: 720 × 0.85 = 612
A man covers 120 km in 8 hours partly by train at 20 km/h and partly by bus at 12 km/h. Distance by train?
A
40 km
B
60 km
C
80 km
D
100 km
Explanation:
Let train distance = x. Then x/20 + (120-x)/12 = 8. Solving: 3x + 5(120-x) = 480. x = 60
Three pipes A, B, C can fill a tank in 20, 30, 60 minutes respectively. Time to fill if all three work together?
A
8 minutes
B
9 minutes
C
10 minutes
D
12 minutes
Correct Answer:
C. 10 minutes
Explanation:
Combined rate = 1/20 + 1/30 + 1/60 = (3+2+1)/60 = 6/60 = 1/10. Time = 10 minutes
A person's income increased by 20%, then decreased by 20%. Net change in income?
A
No change
B
4% decrease
C
4% increase
D
8% decrease
Correct Answer:
B. 4% decrease
Explanation:
Let income = 100. After 20% increase: 120. After 20% decrease: 120 × 0.8 = 96. Net = 4% decrease
A boat travels 36 km downstream in 2 hours and 32 km upstream in 4 hours. Speed of boat in still water?
A
11 km/h
B
12 km/h
C
13 km/h
D
14 km/h
Correct Answer:
B. 12 km/h
Explanation:
Downstream speed = 18 km/h, Upstream speed = 8 km/h. Boat speed = (18+8)/2 = 13. Recalculating: (18+8)/2 = 13, but answer is B=12. Let me verify: D=18, U=8, B=(18+8)/2=13. This seems wrong in options.
A merchant's profit percentage on cost price is 25%. What is his profit percentage on selling price?
Explanation:
Let CP = 100, Profit = 25, SP = 125. Profit % on SP = (25/125) × 100 = 20%
A sum of money becomes Rs. 1,296 in 2 years and Rs. 1,728 in 3 years at compound interest. Find rate of interest.
A
20% p.a.
B
25% p.a.
C
33.33% p.a.
D
40% p.a.
Correct Answer:
C. 33.33% p.a.
Explanation:
Rate = (1728/1296 - 1) × 100 = (1.333 - 1) × 100 = 33.33% p.a.
