Arithmetic - Online Test
Q1. If 137+276=435 how much is 731+672?
Answer : Option C
Explaination / Solution:
No Explaination.
Q2. X takes twice as much time as Y to complete a work and Z does it in the same time as X and Y together. If all three working together can finish the work in 6 days then what is the time taken by X, Y and Z respectively?
Answer : Option D
Explaination / Solution:
Let 2T days and T days be the time taken to complete the work by X and Y respectively.
1/2T and 1/T be the work done in 1 day by X and Y respectively.
1/2T + 1/T= 3/2T be the total work done by X and Y together in 1 day.
2T/3 days be the time taken by Z to complete the work.
According to the question,
1/T + 1/2T + 3/2T = 1/6
Or, T = 18 days
2T = 36 days and 2T/3 = 12 days
Q3. Two trains are running at 48 km/hr and 42 km/hr respectively in the opposite direction. Slow train is having half of the length of the other train and they crosses each other in 12 seconds. The faster train also passes a railway platform in 45 seconds. What is the length of the platform?
Answer : Option E
Explaination / Solution:
Let ‘x’ meter and’ x/2’ meter be the length of the first and second train respectively.
Relative speed = 48+42 = 90 km/hr = 25 m/s
now, Distance/Speed = time
Or, ((x+(x/2)) / 25 = 12
Or, x= 200 meter
Length of the first train = 200 m
Let ‘y ’ meter be the length of the platform.
Speed of the first train = 48 km/hr = 40/3 m/s
(200+y) / (40/3) = 45
Or, y = 400 m
Q4. 56 men can do a job in 14 days. How many additional men are required to do the same job in 8 days?
Answer : Option A
Explaination / Solution:
Therefore, required number of additional men = 98 – 56 = 42.
Q5. The average speed of a train is 
times the average speed of a tractor. The tractor covers 270 km in 15 hours. How much distance will the train cover in 12 hours?
times the average speed of a tractor. The tractor covers 270 km in 15 hours. How much distance will the train cover in 12 hours?
Answer : Option D
Explaination / Solution:
Speed of the tractor = 270/15 = 18km/h
Speed of the train = 13/3 × 18 = 78 km/h
Distance covered by the train in 12 hours
= 78 × 12 = 936 km
Q6. Total age of Ramesh and Sohan is 30 years more than that of Sohan and Mahesh. While the average age of Ramesh, Sohan and Mahesh is equal to that of Ramesh and Sohan. Then what is the difference between the ages of Ramesh and Sohan?
Answer : Option B
Explaination / Solution:
R + S = S + M + 30
Or R - M = 30 .......(I)
And (R+S+M)/3 = (R+S)/2
3R + 3S = 2R + 2S + 2M
Or M = (R+S)/2 ........(II)
Putting (II) in (I)
R - (R+S)/2 = 30 => R-S = 60
Q7. A passenger train departs from Chennai at 8 p.m. for Madurai. At 11 p.m an express train, whose average speed exceeds that of the passenger train by 15 km/hr, leaves Madurai for Chennai. Two trains meet each other mid-route. At what time do they meet, given that the distance between the cities is 1080 km?
Answer : Option A
Explaination / Solution:
Let speed of passenger train = x
Speed of express train = x +15
Let they after 1 hour
So distance travelled by both is same = 1080/2 = 540
Distance travelled by passenger train = x(t+3)
Distance travelled by express train = (x + 15)t
=> x(t+3) = (x + 15)t
x = 5t
Total distance = 1080
x(t+3) + (x + 15)t = 1080
t2 + 3t-108 = 0
so t = 9, -12
They meet after 9 hours
Time = 11:00 + 9:00 pm = 8 : am
Q8. The average marks in a class of 40 students is 72. Later it was found that 20% students weren't awarded marks in a 5 marks question which they had attempted correctly. So, their marks were increased. What is the new average of the marks obtained by the class?
Answer : Option B
Explaination / Solution:
Average = (Sum of the marks of all the students in the class)/ (Number of students in the class).
So, 72 = Sum/40 →
Sum = 72 40.
Now as 20% students i.e. 20% 0f 40 = 8 students get their marks increased by 5 marks each → The total increase in the sum of the total marks of the class = Sum + 8(E. = 72(40) + 40 = 73(40).
So, new average = New Sum / 40 = 73(40) / 40 = 73 marks.
Q9. The current age of Suman and Monika are in the ratio 5 : 3. Ten years from now, their ages will be in the ratio 10 : 7 then, Monika's current age is :
Answer : Option C
Explaination / Solution:
Let,
Suman’s age = 5x
Monika’s age = 3x
According to the question,
(5x + 10)/(3x+10) = 10/7
35x + 70 = 30x + 100
x = 6
so, Monika's present age = 3x
= 3 × 6 = 18 years
Q10. Three years ago the average age of Mohan’s family having 5 members was 17 years. Mohan becomes father but the average age of his family is same today. What is the present age of baby?
Answer : Option B
Explaination / Solution:
The age of 5 members 3 years ago=17×5=85 years
Total age of 5 members at present= 85 + (5×3)=100 years
Total age of 6 members at present =17×6=102 years…
(as average is same at present so we took 17)
Hence, age of baby = 102-100 = 2 years
