Answer: The cost of 16 pencils and 10 notebooks is $5.84.
Explanation: You can solve this using linear systems:
Let X be the cost per pencil, and let Y be the cost per notebook.
(1) 7x+8y=4.15 (2) 5x+3y=1.77
Choose a variable to eliminate. I’ll eliminate X first as an example. To eliminate a variable, you must have the same coefficient beside the variable for both equations.
Equation 1 now becomes:
(3) 35x+40y=20.75
Equation 2 now becomes:
(4) 35x+21y=12.39
Now that you have 35 as a coefficient for X in both equations, you can subtract the two equations to officially eliminate it!
(3)-(4)
19y=8.36 y=0.44
Now that you have the value of Y, substitute that value into either one of the equations to get X.
Substitute y=0.44 in (1)
7x+8(0.44)=4.15 7x+3.52=4.15 7x=0.63 x=0.09
Therefore, the cost per pencil is $0.09/pencil and the cost per notebook is $0.44/notebook.
Almost done lol...
To find the cost of 16 pencils, multiply 0.09*16. That gives you $1.44, which will be the cost of 16 pencils. The cost of 10 notebooks is 0.44*10, which gives you $4.40. That’s the cost of 10 notebooks.
To find the total price, add these values together!
1.44+4.40=5.84
Therefore, the cost of 16 pencils and 10 notebooks is $5.84.
