Exams

Let the value to be find be 'x'.

 
Sum of individual column value = 14

 
C1 = 7 + 2 + 1 + 4 = 14
C2 = 3 + 8 + 1 + 2 = 14
C3 = 6 + 5 + 2 + 1 = 14

C4 = 2 + 4 + 4 + x = 14

x = 14 - 10

x = 4

Hence, the missing number is '4'.

The F1, F2 to F12 keys that are found on the top row of most computer keyboards are called as Function Keys. Unless you've witnessed the evolution of computers from their early days, you probably don't know why they were invented and for what.
Function keys were used by various computer programs to fulfill various functions.

F12 - It is used by many web browsers to open the developer tools.

Given P = 54 and M = 80

According to the question,

Let ‘A’ years ago, M = 3P

=> M - A/P - A = 3

=> 80 - A = 3(54 - A)

=> 80 - A = 162 - 3A

=> 2A = 82

=> A = 41

Therefore, A = 41 years ago Sweety’s mother was 3 times of Sweety’s age.

Hence, at the age S = 13 and M = 39.

Weight is mass x g. Since mass is constant and g is only 16thof that on the earth. The weight on the moon is only 16th of that on the earth. 

Therefore 2N i.e (b) is the answer.

Let the third subject marks be 'x'
=> Second subject marks = 2x
=> Third subject marks = 4x
Given avg = 224
x + 2x + 4x = 224 x 3
=> 7x = 224 x 3
=> x = 96
Hence, Second subject marks = 2x = 2 x 96 = 192.

Rajesh   - 8 years

Ramesh - 6 or 7 years

Ravi      - 5 years

Raghu   - 3 years

Let the distance in one direction = k kms

Speed in still water = 4.5 kmph

Speed of river = 1.5

Hence, speed in upstream = 4.5 - 1.5 = 3 kmph

Speed in downstream = 4.5 + 1.5 = 6 kmph

Time taken by Rajesh to row upwards = k/3 hrs

Time taken by Rajesh to row downwards = k/6 hrs

Now, required Average speed =$$\begin{gathered} Total distanceTotal speed = 2kk3 + k6 \\ = 2k x 186k + 3k = 4 kmph \end{gathered}$$ 

Therefore, the average speed of the whole journey = 4kmph.