General Mathematics & Basic Arithmetic — Part 3 MCQs with Explanations

Given: Average of 5 numbers = 4 2 is added to each number. Formula: Average = Sum of numbers ÷ Number of numbers Original Sum = 4 × 5 = 20 After adding 2 to all 5 numbers: New Sum = 20 + (2 × 5) = 30 New Average = 30 ÷ 5 = 6

Given: Total books = 24,375 Books per shelf = 375 Formula: Number of shelves = Total books/ Books per shelf 24375/375 = 65 ​

Speed = 12 km/h Time = 15 minutes = 15/60 = 1/4 hour Formula: Distance = Speed x Time = 12 x 1/4 = 12 times frac{1}{4} = 3 km

Series: 13, 32, 24, 43, 35, ?, 46, 65, 57, 76 Notice the pattern alternates: +19, −8, +19, −8, +19, −8, +19, −8, +19 So: 35 + 19 = 54 Then 54 − 8 = 46, which matches. Missing number = 54

Average = Sum of numbers Number of numbers ​ So: Sum = Average × Number of numbers = 33 x 3 = 99 ​

Let the present age of the son = x years. Present age of the father = 45 − x years. 5 years ago: Father's age = 40 − x Son's age = x − 5 According to the question: 40 − x = 6(x − 5) 40 − x = 6x − 30 70 = 7x x = 10 Son's present age = 10 years. Father's present age = 45 − 10 = 35 years.

A regular hexagon has 6 equal sides. Perimeter = 6 × side = 6 × 7 = 42 cm .

The sum of the interior angles of a polygon can be calculated using the formula: (n-2) × 180°, where n is the number of sides. For a hexagon, n = 6. Sum of interior angles = (6-2) × 180° = 4 × 180° = 720°

An acute angle measures more than 0° but less than 90° . Since 60° is less than 90° , it is an acute angle. Additional information : A right angle measures exactly 90° . An obtuse angle measures more than 90° but less than 180° .

Total = (Position from left) + (Position from right) - 1 = 7 + 12 - 1 = 18

1², 2², 3², 4², 5² 1, 4, 9, 16, 25

At 3:00, the minute hand is at 12 and the hour hand is at 3. The angle between them is 90° (a right angle).

Day after tomorrow = 3 days before Thursday 3 days before Thursday = Monday So: Day after tomorrow = Monday Tomorrow = Sunday Today = Saturday

Total students = 15 + 20 = 35 Female = 20 Fraction female = 20/35 = 4/7 .

(18 + 24 + 30 + 36 + x) / 5 = 30 108 + x = 150 x = 42

Divide the numerator by the denominator. 3 ÷ 4 = 0.75

Rule: A number is divisible by 9 if sum of its digits is divisible by 9. 326 = 3+2+6 = 11 - No 324 = 3+2+4 = 9 - Yes 325 = 3+2+5 = 10 - No

Old diameter = D New diameter = D + 50% of D = 1.5 D So new radius = 1.5 r Area = pi _ r^2 Old area = pi _ r^2 New area = pi _ (1.5 r)^2 = pi _ 2.25 _ r^2 = 2.25 _ old area Increase = 2.25 - 1 = 1.25 = 125%

Total work = 72 workers 40 days = 2880 worker-days For 64 workers: Days = 2880 / 64 = 45 days

Let son's age now = x Father's age now = 4x After 20 years: Son = x + 20 Father = 4x + 20 According to question: 4x + 20 = 2 * (x + 20) 4x + 20 = 2x + 40 4x - 2x = 40 - 20 2x = 20 x = 10 Son is 10 years old now (Father is 40).

(x-2)/3 + (x-4)/10 = x/2 Take LCM of 3,10,2 = 30 and multiply both sides by 30 10_(x-2) + 3_(x-4) = 15*x 10x - 20 + 3x - 12 = 15x 13x - 32 = 15x -32 = 15x - 13x -32 = 2x x = -16

Maryam = x Bilal = x - 3 (because Maryam has 3 more than Bilal) Jameel = x + 5 (because Maryam has 5 less than Jameel) Jameel + Bilal = (x + 5) + (x - 3) = 2x + 2

Average speed = Total distance / Total time Time 1 = 60 / 40 = 1.5 h Time 2 = 60 / 60 = 1 h Total time = 2.5 h Average = 120 / 2.5 = 48 km/h

4 × 5 × q = 5 × p × 2 20q = 10p p/q = 20/10 = 2

For fourth proportion: a : b = c : d 5 : 8 = 10 : x 5/8 = 10/x 5x = 80 x = 16

Circumference formula: C = π × d 18π = π × d d = 18

Let six consecutive even numbers be: x, x+2, x+4, x+6, x+8, x+10 Average = (6x + 30) / 6 = x + 5 = 35 x = 30 Numbers are: 30, 32, 34, 36, 38, 40 Largest = 40

Average = (4 + 8 + 12 + 16 + 20) / 5 = 60 / 5 = 12

LCM of 18 and 24 18 = 2 × 3² 24 = 2³ × 3 LCM = 2³ × 3² = 8 × 9 = 72

845 ÷ 7 7 × 120 = 840 845 - 840 = 5 Remainder = 5

3/4 + 1/8 = 6/8 + 1/8 = 7/8

x + 25% of x = 250 x × (1 + 0.25) = 250 x × 1.25 = 250 x = 250 / 1.25 = 200

15% of 240 = (15/100) × 240 = 0.15 × 240 = 36 Last updated by NA on 24-April-2026

3 dozen = 36 eggs Price of 36 eggs = Rs. 750 Price of 1 egg = 750 ÷ 36 = Rs. 20.83 Price of 5 eggs = 20.83 × 5 = Rs. 104.17

Let the number be x. 4x - 4 = 16 Add 4 to both sides: 4x = 20 Divide by 4: x=5

Person B has = 55 sweets Person A gives = 4 sweets So, B receives 4 more sweets: 55+4= 59

Girls = 60 Girls are 3 times the boys. Boys = 60 ÷ 3 = 20 Adil is 12th among the boys. Boys ahead of him = 12 − 1 = 11

Selling Price (SP) = $2400 Profit = 20% SP = 120% of the Cost Price (CP) CP = 2400 × 100 ​/ 120= $2000

. Starts facing North, moves 7 km North. 2. Turns West, moves 2 km. 3. Turns South, moves 4 km → Now he's (7 - 4) = 3 km North from start. 4. Turns West again, moves another 2 km → Total 4 km West. So, from the starting point, he's 3 km North and 4 km West. Use Pythagoras theorem to find the distance from the start: Distance = √(3² + 4²) = √(9 + 16) = √25 = 5 km

An octagon has 8 sides. ⬡ Interior Angle Sum : 1,080° Regular Octagon: All 8 sides and angles are equal. Each Interior Angle: 135 ° Example: Stop sign