Question

Help please!!! You are Miguel Cervantes de Navas y Colon, captain in the Royal Spanish Army in Sevilla in the year 1842

Answer 1

There are 650 cannonballs

Explanation:

If you look closely in the picture, you can see that:

• 1st row has 1 ball
• 2nd row has 4 balls
• 3rd row has 9 balls
• 4th row has 16 balls

etc. etc.

We can see that the number of balls is the square of the row number. There are a total of 12 rows. So, rest of the rows has:

• 5th row has 25 balls
• 6th row has 36 balls
• 7th row has 49 balls
• 8th row has 64 balls
• 9th row has 81 balls
• 10th row has 100 balls
• 11th row has 121 balls
• 12th row has 144 balls

If we add up all those, we get total number of balls:

`1+4+9+16+25=36+49+64+81+100+121+144=650`

There are 650 cannonballs

Answer 2

we can start from top

we can see that

top has 1 ball

second top has 4 balls

third top has 9 balls

so, we will get series

`1^2 +2^2+3^2+4^2+...........+12^2`

now, we can add them

we can sum of squares of natural numbers formula

`Sum=(n(n+1)(2n+1))/(6)`

Here , last term is 12^2

so, n=12

`Sum=(12(12+1)(2*12+1))/(6)`

we will get

`Sum=650`

so, number of balls is 650...........Answer