Question

the sum of three consecutive multiple of 7 is 777

Answer 1

First no. :x
Second no. : x+7
Third no. : x+14
A.T.Q
x+x+7+x+14=777
3x+21=777
3x=756
x=252
first no. 252
second no. 259
third no. 266

Answer 2

$\: Let \: the \: three \: consecutive \: multiples \: \: be \: x \\ x + (x + 7) + (x + 14) = 777 \\ 3x + 21 = 777 \\ 3x = 777 - 21 \\ 3x = 756 \\ x = \frac{756}{3} \\ x = 252 \\ \: \: Hence, \: \: the \: three \: consecutive \: multiples \: are \: 252, \: 259 \: and \: 266.$