1. Let $l_x$ denote the number of those original lives aged 0 who will still be alive
at age $x$, $nq_x$ be the probability that ($x$) will die at the ages between $x$ and
$x+n$ and $e_x$ be the curtate life expectancy. You are given that $q_{60} = 0.25$,
$q_{61} = 0.28$, $q_{62} = 0.29$, $q_{63} = 0.30$, $q_{64} = 0.35$.
(a) Find $l_x$ for ages 61 to 65, beginning with $l_{60} = 1000$.