1. In a three digit number, the hundred digit is 2 more than the tens digit and the units digit is 2 less than the tens digit. If the sum of the digits is 18, find the number?.
- 975
- 753
- 642
- None of these
4
-
View Answer
Solution:
Let the three digit numbers be 100a + 10b + c
a = b + 2
c = b - 2
a + b + c = 3b = 18 => b = 6
So a = 8 and b = 4
Hence the three digit number is: 864
2. How long does a train 165 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length?
- 45 sec
- 50 sec
- 55 sec
- 74 sec
7
3. Two pipes A and B can fill a cistern in 20 and 30 minutes respectively, and a third pipe C can empty it in 40 minutes. How long will it take to fill the cistern if all the three are opened at the same time?
- 19 1/7 min
- 15 1/7 min
- 17 1/7 min
- 7 1/7 min
11
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View Answer
Solution:
1/20 + 1/30 - 1/40 = 7/120
120/7 = 17 1/7
4. The proportion of copper and zinc in the brass is 13:7. How much zinc will there be in 100 kg of brass?
- 20 kg
- 35 kg
- 55 kg
- 14 kg
14
5. One train is traveling 45 kmph and other is at 10 meters a second. Ratio of the speed of the two trains is?
- 5:4
- 4:5
- 9:2
- 2:9
17
6.What is the difference between the local value of 7 and 5 in the number 2574?
- 570
- 430
- 403
- 413
22
7. The product of two numbers is 2025 and their HCF is 15 their LCM is:
- 204
- 201
- 135
- 150
27
8. How many seconds will a train 100 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
- 18
- 20
- 25
- 28
31
-
View Answer
Solution:
D = 100 + 150 = 250
S = 36 * 5/18 = 10 mps
T = 250/10 = 25 sec
9. 85% of a number is added to 24, the result is the same number. Find the number?
- 130
- 140
- 150
- 160
36
-
View Answer
Solution:
(85/100) * X + 24 = X
3X = 480
X = 160
10. If a solid sphere of radius 10 cms is moulded into 8 spherical solid balls of equal radius, then surface area of each ball (in cm2) is?
- 100π
- 7π
- 60π
- 50π
37
-
View Answer
Solution:
4/3 π * 10 * 10 * 10 = 8 * 4/3 πr3
r = 5
4π * 5 * 5 = 100π
11. Ramesh can finish a work in 20 days and Sushil in 25 days. They both work together for 5 days and then Sushil goes away. In how many days will Ramesh complete the remaining work?
- 8 days
- 9 days
- 10 days
- 11 days
44
-
View Answer
Solution:
(5 + x)/20 + 5/25 = 1 => x = 11 days
12.A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If three marbles are drawn what is the probability that one is yellow and two are red?
- 24/455
- 3/91
- 12/455
- 15/91
47
-
View Answer
Solution:
Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.
When three marbles are drawn, the probability that one is yellow and two are red
= (²C₁)(⁴C₂)/¹⁵C₃
= (2 * 4 * 3 * 3 * 2)/(1 * 2 * 15 * 14 * 13) = 12/455
14.40 is subtracted from 60% of a number, the result is 50. Find the number?
- 150
- 140
- 130
- 110
53
-
View Answer
Solution:
(60/100) * X – 40 = 50
6X = 900
X = 150
15. A sells his goods 50% cheaper than B but 50% dearer than C. The cheapest is?
- A
- B
- C
- All Alike
59
-
View Answer
Solution:
Let B = 100
A = 50
C * (150/100) = 50
3C = 100
C = 33.3 then 'C' Cheapest
16.A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If three marbles are picked at random, what is the probability that they are all blue?
- 1/455
- 2/455
- 1/91
- 4/455
61
-
View Answer
Solution:
Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.
Probability that all the three marbles picked at random are blue = ³C₃/¹⁵C₃ = (1 * 3 * 2 * 1)/(15 * 14 * 13) = 1/455
17.A man sells two articles for Rs.3600 each and he gains 30% on the first and loses 30% on the next. Find his total gain or loss?
- 9% loss
- 400
- 4000
- 324
65
18.A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If two marbles are picked at random, what is the probability that they are either blue or yellow?
- 3/22
- 4/21
- 2/21
- 1/14
71
-
View Answer
Solution:
Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.
Probability that both marbles are blue = ³C₂/¹⁵C₂ = (3 * 2)/(15 * 14) = 1/35
Probability that both are yellow = ²C₂/¹⁵C₂ = (2 * 1)/(15 * 14) = 1/105
Probability that one blue and other is yellow = (³C₁ * ²C₁)/¹⁵C₂ = (2 * 3 * 2)/(15 * 14) = 2/35
Required probability = 1/35 + 1/105 + 2/35
= 3/35 + 1/105 = 1/35(3 + 1/3)
= 10/(3 * 35) = 2/21
19. A can finish a piece of work in 5 days. B can do it in 10 days. They work together for two days and then A goes away. In how many days will B finish the work?
- 4 days
- 5 days
- 6 days
- 8 days
73
-
View Answer
Solution:
2/5 + (2 + x)/10 = 1 => x = 4 days
