Missing number

Question

(21,7,2), (6,?,1), (24,6,3), (56,14,3)

Answer 1

(21,7,2), (6,?,1), (24,6,3), (56,14,3)

 

The pattern in the 1st, 3rd and 4th parenthesis

is the first number in the set is equal to the 2nd

number multiplied by the sum of the 3rd number and 1

 

21 = 7(2+1)

24 = 6(3+1)

56 = 14(3+1)

 

This means the 2nd number in the set (6,?,1) is found by

x(1+1)=6

2x = 6

x = 3

 

Your set is (6,3,1)