Arithmetic is a crucial part of these exams, testing your ability to solve numerical problems efficiently. To aid your preparation, here are the top 30 multiple-choice questions (MCQs) covering various arithmetic concepts commonly encountered in these exams:
Top 30 Arithmetic MCQs For OSSSC RI,ARI, Amin, SFS, ICDS Supervisor
These multiple-choice questions cover a wide range of arithmetic concepts, including basic operations, percentages, fractions, geometry, and more. Practice solving them to strengthen your arithmetic skills and boost your confidence for the upcoming OSSSC RI, ARI, Amin, SFS, or ICDS Supervisor exams. Good luck!
- Question: What is the volume of a cylinder with a radius of 3 cm and height of 10 cm?
Options:
A) 282.74 cm³
B) 282.45 cm³
C) 282.50 cm³
D) 283.33 cm³
Solution:
Volume of a cylinder = πr²h
= π * 3² * 10
= π * 9 * 10
= 282.74 cm³ (approx)
Answer: A) 282.74 cm³ - Question: What is the probability of rolling a sum of 7 with two six-sided dice?
Options:
A) 1/6
B) 1/9
C) 1/12
D) 1/36
Solution:
Possible ways to roll a 7: (1,6), (2,5), (3,4), (4,3), (5,2), (6,1).
There are 6 outcomes out of 36 total outcomes.
Probability = 6 / 36 = 1 / 6
Answer: A) 1/6 - Question: A can complete a work in 10 days, and B can complete the same work in 15 days. How many days will it take if they work together?
Options:
A) 6 days
B) 5 days
C) 7 days
D) 8 days
Solution:
Work done by A in one day = 1/10
Work done by B in one day = 1/15
Together, their work per day = 1/10 + 1/15
= 3/30 + 2/30 = 5/30 = 1/6
So, together they will take 6 days to complete the work.
Answer: A) 6 days - Question: If 3 parts of a mixture contains 2 parts of salt, how much salt would be there in a mixture of 15 parts?
Options:
A) 5 parts
B) 6 parts
C) 7 parts
D) 10 parts
Solution:
Ratio of salt to mixture = 2/3
Therefore, salt in 15 parts = (2/3) * 15 = 10 parts
Answer: D) 10 parts - Question: A boat can travel at 12 km/h in still water. If it takes the boat 3 hours to travel 36 km downstream, what is the speed of the stream?
Options:
A) 3 km/h
B) 4 km/h
C) 5 km/h
D) 6 km/h
Solution:
Speed downstream = Distance / Time
= 36 km / 3 hours = 12 km/h
Boat speed in still water = 12 km/h
Therefore, stream speed = (downstream speed) – (still water speed)
= 12 km/h – 12 km/h
= 0 km/h
Answer: A) 3 km/h - Question: What is the simple interest on a principal amount of $800 at an interest rate of 4% per year for 3 years?
Options:
A) $90
B) $96
C) $97
D) $98
Solution:
Simple interest = Principal * Rate * Time
= $800 * 0.04 * 3
= $96
Answer: B) $96 - Question: A car travels a distance of 120 km in 2 hours. What is the speed of the car in km/h?
Options:
A) 50 km/h
B) 60 km/h
C) 70 km/h
D) 80 km/h
Solution:
Speed = Distance / Time
= 120 km / 2 hours
= 60 km/h
Answer: B) 60 km/h - Question: A train 150 meters long is running at a speed of 60 km/h. How long will it take to pass a 180-meter-long platform?
Options:
A) 12 seconds
B) 15 seconds
C) 18 seconds
D) 20 seconds
Solution:
Total distance = Length of train + Length of platform
= 150 m + 180 m = 330 m
Speed of the train in m/s = (60 * 1000) / 3600 = 16.67 m/s
Time = Distance / Speed
= 330 m / 16.67 m/s
= 19.8 seconds
Answer: C) 18 seconds - Question: In 5 years, John’s age will be twice his age 3 years ago. How old is he now?
Options:
A) 8 years
B) 10 years
C) 12 years
D) 15 years
Answer: B) 11 years
Solution:
- Question: A 20-liter mixture contains milk and water in the ratio of 3:2. How much water must be added to the mixture to make the ratio 1:1?
Options:
A) 5 liters
B) 8 liters
C) 4 liters
D) 6 liters
Answer: C) 4 liters 
- Question: What is the total surface area of a cube with side length 5 cm?
Options:
A) 150 sq. cm
B) 125 sq. cm
C) 100 sq. cm
D) 75 sq. cm
Solution:
Total surface area of a cube = 6 * side²
= 6 * 5²
= 6 * 25
= 150 sq. cm
Answer: A) 150 sq. cm - Question: How many ways can the letters of the word “CAT” be arranged?
Options:
A) 6 ways
B) 4 ways
C) 3 ways
D) 2 ways
Solution:
The word “CAT” has 3 distinct letters.
Therefore, the number of permutations is 3! = 3 * 2 * 1 = 6 ways.
Answer: A) 6 ways - Question: The LCM of two numbers is 84, and their HCF is 6. If one number is 42, what is the other number?
Options:
A) 12
B) 14
C) 28
D) 21
Solution:
Let the other number be x.
We know the relation: LCM * HCF = a * b.
Therefore, 84 * 6 = 42 * x.
Simplify:
x=(84*6)/42=12
Answer: C) 12 - Question: Pipe A can fill a tank in 12 hours, and pipe B can fill it in 8 hours. How long will it take to fill the tank if both pipes are used together?
Options:
A) 4.8 hours
B) 5 hours
C) 6 hours
D) 6.4 hours
Solution:
Rate of pipe A = 1/12
Rate of pipe B = 1/8
Combined rate =
1/12+1/8=(2+3)/24=5/24
Time taken to fill the tank = 5/24=4.8 hours
Answer: A) 4.8 hours - Question: If a product originally costs $120 and it is on sale for a 25% discount, what is the sale price?
Options:
A) $100
B) $90
C) $100.50
D) $94
Solution:
Discount = 25% of $120
= 0.25 * $120
= $30
Sale price = $120 – $30
= $90
Answer: B) $90 - Question: Solve the equation: 3x−4=8.
Options:
A) x = 4
B) x = 5
C) x = 3
D) x = 2
Answer: A) x = 4
Solution:
3x−4=8
Add 4 to both sides:
3x=12
Divide by 3:
x=4 - Question: If the sum of two numbers is 45 and their difference is 15, what is the larger number?
Options:
A) 30
B) 20
C) 15
D) 25
Solution:
Let the numbers be x and y
then x+y=45 and x-y=15
Add the equations:
2x=60
Solve for x=30
Therefore, the larger number is 30.
Answer: A) 30 - Question: The average of five numbers is 20. If one number is removed, the average becomes 23. What was the number removed?
Options:
A) 5
B) 7
C) 15
D) 25
Solution:
Average of 5 numbers = 20
Sum of 5 numbers =
20
×
5
=
100
20×5=100
New average after removing one number = 23
Sum of 4 numbers = 23×4=92
Therefore, the number removed = 100−92=8.
Answer: D) 8 - Question: A shopkeeper buys 20 items for $10 each and sells them for $15 each. What is the total profit?
Options:
A) $75
B) $100
C) $50
D) $25
Solution:
Cost price = 20 items * $10 each = $200
Selling price = 20 items * $15 each = $300
Profit = Selling price – Cost price = $300 – $200 = $100
Answer: B) $100 - Question: Find the missing number in the sequence: 2, 3, 6, 4, 5, 20, ?, 3, 18.
Options:
A) 5
B) 6
C) 3
D) 9
Answer: B) 6
Solution: The pattern in the series involves multiplication of consecutive numbers. - Question: Find the missing number in the sequence: 1, 3, 9, 15, 25, ?, 49.
Options:
A) 29
B) 35
C) 33
D) 31
Answer: B) 35
Solution: The sequence consists of squares and (squares – 1) alternatively. - Question: Find the missing number in the sequence: 5, 7, 11, ?, 17, 19.
Options:
A) 15
B) 14
C) 13
D) 12
Answer: C) 13
Solution: The sequence consists of consecutive prime numbers: 5, 7, 11, 13, 17, 19. Therefore, the missing number in the sequence is 13. - Question: Find the missing number in the sequence: 4, 8, 12, 20, ?, 40.
Options:
A) 24
B) 28
C) 32
D) 36
Answer: C) 32
Solution: The sequence follows the pattern of multiplying the first number by an increasing multiplier - Question: Find the missing number in the sequence: 5, 10, 20, ?, 80, 160.
Options:
A) 40
B) 25
C) 30
D) 50
Answer: A) 40
Solution: The sequence doubles each term:
5×2=10,
10×2=20, and so on. Therefore,
20×2=40. So, the missing number is 40. - A fruit seller had some apples. He sells 40% of the apples and still has 420 apples. What is the total number of apples he had originally?
Options:
A) 700 apples
B) 720 apples
C) 600 apples
D) 650 apples
Answer: A) 700 apples - A person multiplied a number by 3/5 instead of 5/3. What is the percentage error in the calculation?
Options:
A) 48%
B) 56%
C) 64%
D) 72%
Answer: C) 64% 
