A person borrows ₹25,000 at 8% SI. After 3 years, how much total amount must he repay?
A
₹31,000
B
₹31,500
C
₹32,000
D
₹33,000
Correct Answer:
A. ₹31,000
Explanation:
SI = (25000 × 8 × 3)/100 = ₹6000. Total = 25000 + 6000 = ₹31,000
A train 250 meters long passes a platform 150 meters long in 20 seconds. Find the speed of the train.
A
54 km/h
B
64.8 km/h
C
72 km/h
D
90 km/h
Correct Answer:
C. 72 km/h
Explanation:
Total distance = 250 + 150 = 400 meters. Time = 20 seconds. Speed = 400/20 = 20 m/s = 20 × 18/5 = 72 km/h
The LCM of two coprime numbers is 143. If one number is 11, find the other.
Explanation:
For coprime numbers, HCF = 1. So LCM = Product. 143 = 11 × x. Therefore x = 13. Check: HCF(11,13) = 1 ✓
HCF of two numbers is 11 and their sum is 99. If one number is 33, find the other number.
Explanation:
If HCF = 11, both numbers are multiples of 11. Sum = 99, one number = 33. Other = 99 - 33 = 66. Check: HCF(33,66) = 33. Correction: Numbers are 11×3=33 and 11×6=66. HCF = 11 ✓
A product's cost price is ₹500. A trader marks it 60% above cost price and gives a discount of 25%. If HCF of profit and marked price is calculated, find the profit percentage.
Explanation:
MP = 500 × 1.60 = ₹800. SP = 800 × 0.75 = ₹600. Profit = 100. Profit% = (100/500) × 100 = 20%
Three numbers are in the ratio 2:3:4 and their LCM is 240. Find the HCF of these numbers.
Explanation:
Let numbers be 2k, 3k, 4k. LCM(2k, 3k, 4k) = 12k = 240, so k = 20. HCF = k = 20
The HCF of two numbers is 12 and their LCM is 180. If one number is 36, find the other number.
Explanation:
Using HCF × LCM = Product of two numbers. 12 × 180 = 36 × x. Therefore x = 2160/36 = 60
Three bells ring at 8, 12, and 18-minute intervals. After how many minutes will they ring together if they start together?
A
36 minutes
B
48 minutes
C
60 minutes
D
72 minutes
Correct Answer:
D. 72 minutes
Explanation:
LCM(8, 12, 18) = LCM(2³, 2²×3, 2×3²) = 2³×3² = 8×9 = 72 minutes
If a profit of ₹200 is made on a book by selling at 20% profit, what is the selling price?
A
₹1000
B
₹1200
C
₹1400
D
₹1500
Explanation:
Profit = 20% of CP; ₹200 = 0.2×CP; CP = ₹1000; SP = 1000 + 200 = ₹1200
A merchant offers successive discounts of 15% and 10%. What is the equivalent single discount?
A
23.5%
B
25%
C
24%
D
26.5%
Explanation:
After 15% discount: 85%; After 10% on that: 85×90/100 = 76.5%; Single discount = 100-76.5 = 23.5%
