A total of 57 sweets were distributed among 10 children such that each girl gets 6 sweets and each boy gets 5 sweets. The number of boys is:

Let's assume the number of boys and girls are B and G respectively.

A total of 57 sweets were distributed among 10 children such that each girl gets 6 sweets and each boy gets 5 sweets.

B+G = 10    Eq.(i)

5B+6G = 57    Eq.(ii)

Multiply Eq.(i) by 5.

5B+5G = 50    Eq.(iii)

Subtract Eq.(iii) from Eq.(ii).

5B+6G-(5B+5G) = 57-50

5B+6G-5B-5G = 7

G = 7

Put the value of 'G' in Eq.(i).

B+7 = 10

B = 10-7

B = 3

Number of boys = 3