Bob has $150 in his savings account and saves $40 a month

y = 40x + 150

Step-by-step explanation:

He starts with 150.

150

He adds 40 per month. Let x represent months: so every x, he gets 40. With 2 x, he gets 80: so we multiply 40 and x and add that to his starting number.

150 + 40x

And let's represent his end amount of money with y, and set it equal.

150 + 40x = y

For the other question:

x = number of months

Bob = 150 + 40x

Andrea = 100 + 50x

100 + 50x > 150 + 40x

50x > 50 + 40x

10x > 50

x > 5

So starting month 6, Andrea will have saved more than Bob.

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