If you follow Joseph to confirm his birthplace you get from the 1881 and 1901 censuses.
1881 census RG11 3820 folio 90
21 Heaton's House Rumworth Lancashire
Joseph Landry 30 Giviney, Cornwall, Head Married Fireman at cotton factory
Mary J. Landry 26 Manchester, Lancashire, Wife Married
William H. Gandy 5 Manchester, Lancashire, Nephew
plus 1 boarder
Marriages Mar 1876
Gandy Mary Jane Manchester 8d 205
Landry Joseph Manchester 8d 205
1901 census RG13 3747 folio 77
7 Gray Street Manchester Lancashire
Joseph Landry 48 Gwennap, Cornwall, Head Married Engineer saw mill
Mary J Landry 46 Manchester, Lancashire, Wife Married
James W Landry 19 Bolton, Lancashire, Son Fireman saw mill
This birthplace for Joseph confirms the two earlier censuses in Camborne.
1851 census HO107 1914 folio 148
Gwennap Cornwall
William Landary 34 Duloe, Cornwall, Head Married Husbandman
Jane Landary 34 Duloe, Cornwall, Wife Married
William Landary 4 Feock, Cornwall
Stephen Landary 3 Feock, Cornwall
Caroline J Landary 11mths Gwennap, Cornwall
Elizabeth A Landary 11mths Gwennap, Cornwall
Births Jun 1850
Landery Caroline Jane Redruth 9 272
Landery Elizabeth Ann Redruth 9 272
possible marriage
Marriages Dec 1843
Landery William Truro 9 360
Libby Jane Truro 9 360
as a p.s from my experience with historical records it is men's ages that are the moveable feast. In general woman are much more likely to be more exact about their age. I wouldn't know about modern times. I have no idea whether the stereotype about women's ages is correct.
I once listened to an archivist from The National Archives give a talk and say exactly the same thing.
Regards
Valda