Question

Here's a riddle for geniuses :-

The correct answer will be marked as brainliest !!!!!

If there are 30 students in a class and if each of them shakes hand with every other student then what are the highest number of hand shakes possible.

HINT :- The answer is not 900 !!!!!

Only a genius can answer.​

Answer 1

Answer:

30 students....

1st student will shake his hand to 29 students.

2nd students = 28

3rd students = 27

.

.

.

.

Last = 1

Now ,

29 + 28 + 27+.......+2 + 1

n = 29

a = 29

d = -1

Sn = n/2{2a + (n - 1)d}

S29 = 29/2{ 2×29 + ( 29 - 1 )(-1) }

= 29/2 { 58 - 28}

= 29/2 {30}

= (29 × 30)/2

= 29 × 15 = 435 Ans...