Question

Find the number of shot in an incomplete square pile of $16$ courses when the number of shot in the upper course is $1005$ less than in the lowest course.

Answer 1

Let 'n' be the number of shots in a side of the base, then we have,

$n^2-{(n-15)}^2=1005$, hence$n=41$

We have none to fine the no. of shot in an incomplete square pile of $16$ courses when

There are $41$ shot in a side of the base

$\frac{41\cdot 42\cdot 83}{6}-\frac{25\cdot 26\cdot 51}{6}$

$=18296$