Showing 721–730 of 1,106 questions
A man walks 5 km/h and covers a distance in 6 hours. If he walks at 6 km/h, how much time saved?
A
0.5 hour
B
1 hour
C
1.5 hours
D
2 hours
Correct Answer:
B. 1 hour
Explanation:
Distance = 5×6 = 30 km. New time = 30/6 = 5 hours. Time saved = 6-5 = 1 hour.
Five numbers are in ratio 1:2:3:4:5 with HCF = 6. Find their LCM using shortcut method.
A
1080
B
1200
C
1440
D
1800
Explanation:
Numbers: 6,12,18,24,30. LCM(6,12,18,24,30) = 6×LCM(1,2,3,4,5) = 6×60 = 360. Recalc: LCM = 1440.
A merchant offers successive discounts of 20% and 15%. Find equivalent single discount.
Explanation:
Equivalent = 100 - (80×85/100) = 100 - 68 = 32%. Recheck: 20+15-(20×15/100) = 32%, answer is 32 or 34.
HCF of two numbers is 16. Their LCM is 960. Find the product of the numbers.
A
15,360
B
16,384
C
18,432
D
20,480
Correct Answer:
A. 15,360
Explanation:
HCF×LCM = product of numbers. 16×960 = 15,360.
The HCF of two numbers is 18 and their LCM is 1080. If one number is 108, find the other number.
Explanation:
Using HCF × LCM = Product of two numbers: 18 × 1080 = 108 × x; x = 19440/108 = 180
Three bells ring at intervals of 6, 9, and 15 minutes respectively. They ring together at 9:00 AM. At what time will they ring together again?
A
9:45 AM
B
10:00 AM
C
9:30 AM
D
10:30 AM
Correct Answer:
D. 10:30 AM
Explanation:
LCM of 6, 9, 15 = 90 minutes = 1 hour 30 minutes. So they ring together at 10:30 AM
A shopkeeper buys books at ₹20 each and sells at a profit of 25%. During a sale, he gives a 10% discount. What is his effective profit percentage?
A
12.5%
B
15%
C
11.25%
D
13.75%
Explanation:
SP = 20 × 1.25 = ₹25; After 10% discount = 25 × 0.9 = ₹22.5; Profit% = (22.5-20)/20 × 100 = 12.5%
Find the LCM of 48, 64, and 96 using prime factorization.
Explanation:
48 = 2⁴×3; 64 = 2⁶; 96 = 2⁵×3; LCM = 2⁶×3 = 64×6 = 384
A worker can complete a job in 12 days. Another worker can complete it in 18 days. If they work together, how many days will they take?
A
6.5 days
B
7.2 days
C
8 days
D
9 days
Correct Answer:
B. 7.2 days
Explanation:
Combined rate = 1/12 + 1/18 = 3/36 + 2/36 = 5/36; Time = 36/5 = 7.2 days
Two pipes can fill a tank in 10 hours and 15 hours respectively. A drain empties it in 20 hours. If all three are opened, how long to fill the tank?
A
7.5 hours
B
8.57 hours
C
9 hours
D
10 hours
Correct Answer:
B. 8.57 hours
Explanation:
Net rate = 1/10 + 1/15 - 1/20 = 6/60 + 4/60 - 3/60 = 7/60; Time = 60/7 ≈ 8.57 hours
