Chapter 6, Problem 11CCSR

Solution

To find the cost of each type of print.

The correct option is A. $5\times 7$ costs $7, $3\times 5$ costs $5, Wallet costs $3.

Given information:

Cost of one $5\times 7$ type print and three $3\times 5$ type prints and one wallet is $25

Cost of two $5\times 7$ type prints and five $3\times 5$ type prints and one wallet is $42.

Cost of four $5\times 7$ type prints and four $3\times 5$ type prints and two wallets is $54.

Calculation:

Let the cost one $5\times 7$ type print be $\$x$ , one $3\times 5$ type print be $\$y$ and one wallet be $\$z$ .

Set up the three equations.

  $\begin{array}{c}x+3y+z=25\\ 2x+5y+z=42\\ 4x+4y+2z=54\end{array}$

The solution of this system of equations is $x=7,y=5,z=3$ .

That means, one $5\times 7$ costs $7, one $3\times 5$ costs $5, and a Wallet costs $3.

Conclusion:

The correct option is A. $5\times 7$ costs $7, $3\times 5$ costs $5, Wallet costs $3.