Answer :
1 + 3d = n => (n-1) / 3 = d
2n = q
n + d + q = 43
substitute
n + (n-1) / 3 + 2n = 43
n = 13
q = 26
d = 4
2n = q
n + d + q = 43
substitute
n + (n-1) / 3 + 2n = 43
n = 13
q = 26
d = 4