Tea costs $x a packets and coffee $y a packet. Five packets of tea and seven of coffee cost $39.40 while three packets of tea and five of coffee cost $26.20. Work out the cost of a packet of tea

$4.53

Step-by-step explanation:

Let us represent

The cost of a

Packet of tea = x

Packet of coffee = y

Five packets of tea and seven of coffee cost $39.40

5x + 7y = 39.40Equation 1

Three packets of tea and five of coffee cost $26.20.

3x + 5y = 26.20Equation 2

Combining both Equations

5x + 7y = 39.40Equation 1

3x + 5y = 26.20Equation 2

Multiply Equation 1 by 5 and Equation 2 by 7 to eliminate y

25x + 35y = 197 Equation 3

21x + 35y = 183.4Equation 4

Subtract Equation 4 from 3

3x = 13.6

x = 13.6/3

x = $4.53

Therefore, the cost of a packet of tea is $4.53

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

the correct answer is d

hope this