The HCF and LCM of two numbers are 12 and 924 respectively. Then the number of such pairs is
0
1
2
3
Answer: Option C.
Let the numbers be 12x and 12y where x and y are prime to each other.
∴ LCM = 12xy
∴ 12xy = 924
=> xy = 77
∴ Possible pairs = (1,77) and (7,11)
What is the least number which, when divided by 5, 6, 7, 8 gives the remainder 3 but is divisible by 9?
1463
1573
1683
1793
Answer: Option C.
LCM of 5, 6, 7, 8 = 35 × 24 = 840
∴ Required number = 840 k + 3 which is exactly divisible by 9.
For k = 2, it is divisible by 9.
∴ Required number = 840k + 3
= 840 × 2 + 3 = 1683
Three numbers are in the ratio 3:4: 5. The sum of the largest and the smallest equals the sum of the second and 52. The smallest number is
20
27
39
52
Answer: Option C.
Let the numbers be 3x, 4x and 5x.
∴ 5x + 3x = 4x + 52
=> 4x = 52 => x =13
∴ The smallest number = 3x = 3 × 13 = 39
If the radius of a circle is in creased by 50%, its area is increased by
125%
100%
75%
50%
Answer: Option A.
Percentage increase in area
A and B working separately can do a piece of work in 9 and 12 days respectively. If they work for a day alternately with A beginning, the work would be completed in
10 2/3 days
10 1/2 days
10 1/4 days
10 1/3 days
Answer: Option C.
Part of work done by A and B in first two days
Part of work done in first 10 days = 35/36
Remaining work = 1 – 35/36 = 1/36
Now it is the turn of A.
∴ Time taken by A = 1/36 × 9 = ¼
∴ Total time = 10 + ¼ = 10 ¼ days
In a family, the average age of a father and a mother is 35 years. The average age of the father, mother and their only son is 27 years. What is the age of the son?
12 years
11 years
10.5 years
10 years
Answer: Option B.
Father + mother = 2 × 35 = 70 years
Father + mother + son = 27 × 3 = 81 years
Son’s age = 81 – 70 = 11 years
If 5 men or 7 women can earn Rs. 5,250 per day, how much would 7 men and 13 women earn per day?
Rs. 11,600
Rs. 11.700
Rs. 16,100
Rs. 17,100
Answer: Option D.
5 men = 7 women
7 men
Mark Price = 140
7 men + 13 women
Now,
∵ 7 women = Rs. 5250
If A and B together can complete a piece of work in 15 days and B alone in 20 days, in how many days can A alone complete the work?
60
45
40
30
Answer: Option A.
(A + B)’s 1 day’s work =
B’s 1 day’s work =
A’s 1 day’s work =
A alone will do the work in 60 days.
By walking at 3/4 of his usual speed, a man reaches his office 20 minutes later than his usual time. The usual time taken by him to reach his office is
75 minutes
60 minutes
40 minutes
30 minutes
Answer: Option B. of usual time = Usual time + 20 minutes of usual time
= 20 minutes
Usual time = 20 × 3 = 60 minutes