Please can someone help thank you

3:1

Step-by-step explanation:

240 necklaces in one month

180-sold on website

60- sold in shop

180:60

then you would simplify

so the final answer is 3:1

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

correct answer:

b.(19,-2)