Age 1 Age 
of B. of A. 
96 
95 
94 
93 
92 
9 l 
90 
86 
85 
84 
83 
82 
81 
80 
on SurvivorJJjips. 
Probability of B’s furviving A. 
335 
O+l 
X— — X 34 = . II 73 

— X 41 + 17 = .1606 
4X ib6 2 ' 
— x 9 X - x 48 + 1 1 u. 5 = .2049 
9 x 234 2 
1 16 + 9 
x 
16 x 289 
1 24+16 
x ^5 + 431.5=1.2420 
24 x 346 
x 
57 + 1 1 19 =.2720 
34 X 406 
x -—-- x 60 4-2259 = . 2897 
46+24 / 
X 1 -— X 63 4-3999 = - 3 022 
Probability of A’s 
furviving B. 
I - .1 I75 = .8887 
I - .1606 = .8394 
I - .2049 = .795 I 
I 
I - .2420 = .7580 
I - .2y20 = .7280 
I — .2897 = .7103 
.6978 
I - .3022 
46 x 469 2 
It may eafily be feen from thefe fpecimens in what manner 
the probabilities of furvivorfhip between two younger lives are 
deduced from the probabilities between two older lives, pro- 
vided their common difference of age be the fame ; for the 
numbers 17 . . 1 1 9.5 . \ . 431*5? &c. in the 2d, 3d, 4th, &c. 
feries are the fums of the feries next preceding. Thus 17 is 
= 34 x 1 . . . 1 19.5 is = 41 x -14- 17 . . . . 431.5 is = 48 x y 4 
1 19. 5, &c. It may be neceffary to obferve further, that if 
the ages of the two perfons be equal, the probability of furvi- 
vorfhip between them being likewile equal, is expreffed by the 
fraction { ; and that this affords an inftance of the accuracy of 
the foregoing inveftigation ; for the feries expreffing the proba- 
bility in this cafe is the fame with this fra&ion, the chance of 
furvivorfhip becoming then (frnce azzb; a=b-c; a" — 
c-d, &c. ; and b 4- c x a = b +c x b - c = b : - c\ See.) = 
