Let the first part be x and the second part be y.
The two parts must add up to 26:
x+y=26
The problem states that three times the first part and seven times the second part equals 122:
3x+7y=122
From the first equation, express x in terms of y:
x=26−y
Substitute into the second equation:
3(26−y)+7y=122
78−3y+7y=122
78+4y=122
4y=122−78
4y=44
y=11
Substitute back to find x:
x=26−y
x=26−11
x=15
The ratio of the first part to the second part is:
x:y=15:11
Therefore, the ratio of the first and second part is 15:11.