Explanation

(3x-5) = 4(x-5)

3x -5 = 4x -20 

4x -3x = 20 -5

x=15

Explanation

The logic followed here is:

Saqib ranks seventh from the top and twenty-eight from the bottom in the class

Number of students in the class= 7 + 28 -1 

                                                        =  34

Explanation

Given information:

1. The average of the first three numbers (A, B, C) is 15

   $$frac{A + B + C}{3} = 15$$ $$A + B + C = 45$$

2. The average of the last three numbers (B, C, D) is 16

   $$frac{B + C + D}{3} = 16$$ $$B + C + D = 48$$

3. The last number (D) is 19

   $$B + C + 19 = 48$$ $$B + C = 29$$

Finding A

We already have:

$$A + B + C = 45$$

Substituting $B + C = 29$:

$$A + 29 = 45$$$$A = 45 - 29$$ $$A = 16$$

Explanation

Explanation

Clearly, the number of trees in the row =(4+1+4)=9.

Explanation

50 - ( 10 + 25 ) = 15 

Khadija is middle of  15

= 8 + 10 

= 18th

Explanation

3 persons can do 3 jobs in 3 days

1/3 of the work will take 1/3 of the time, so

3 people can do 1 job in 1 day

It will take 1 person 3 times as long, so

1 person can do 1 job in 3 days

7 persons can do 7 times the work in the same time, so

7 persons can do 7 jobs in 3 days

Explanation

Arithmetic mean of 2, 4, 6, 8, 10, and 12
A.M = Sum of terms / No. of terms
A.M = (2 + 4 + 6 + 8 + 10 + 12) / 6
A.M = 42 / 6
A.M = 7

Explanation

Sum of the ages of 3 friends =3×23= 69 years

Sum of the ages of 4 friends =4×23= 92 years

∴ Age of 4th friend = 92 years - 69 years = 23 years.

Explanation

To find the sum of the four numbers, multiply the average by the total count of numbers:

Average = 24

Total count = 4

Sum = Average × Total count

Sum = 24 × 4

Sum = 96