Hunter and Logan built small sand towers on the beach. Hunter built 20 towers, and Logan built 9 towers. Then, the ocean water came up and knocked down 6 of the towers. How many of the boys' sand towers were left standing?

23

Step-by-step explanation:

Given:

Hunter and Logan built small sand towers on the beach.

Hunter built 20 towers, and Logan built 9 towers.

Then, the ocean water came up and knocked down 6 of the towers.

Question asked:

How many of the boys' sand towers were left standing?

Solution:

Number of towers made by Hunter = 20

Number of towers made by Logan = 9

Total towers made by both = 20 + 9 = 29

Number of towers knocked down by the ocean water = 6

Remaining number of towers = 29 - 6 = 23

Thus, 23 sand towers of the boys were left standing.

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b