In a class of 24 students, each student shakes hand with everyone els. In another class of 32 students, each student shakes hand with all other students. What is the difference between total number of hand shakes in the 2 classes?
a) 180
b) 200
c) 22
d) 240
e) 260

1 Answer

Answer :

1 st class : Total Hand shakes = 24 × 23 /2 = 12 × 23 =276
 2nd class :Total Hand shakes =32 × 31 / 2 = 16 × 31 = 496
Difference =220
Answer : c

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