Chapter 4.6, Problem 28STP

To determine

To find: how much amount that is spent on lunch.

Answer to Problem 28STP

The correct answer is $6.

Explanation of Solution

Given:

The cost of friend's lunch is $3 more than yours did.

The total spent for lunch are $15.

1. $6
2. $7
3. $8
4. $9

Calculation:

Assume that amount spent on lunch x dollars.

Because the cost of friend’s lunch is $3 more than yours did, so the cost of friend's lunch is ( x +3)dollars.

The total spent for lunch of is $15.

Translate this verbal sentence into an equation as follows:

Hence, the required equation is,

  $x+\left(x+3\right)=15$

Solve the equation obtained in last step as follows:

  $\begin{array}{l}x+\left(x+3\right)=15Writetheequation\\ \left(x+x\right)+3=15Associativeproperty\\ 2x+3=15Combineliketerms\\ 2x+3-3=15-3Subtract3frombothsides\\ 2x=12Simplify\\ \frac{2x}{2}=\frac{12}{2}Dividebothsidesby2\\ x=6Simplify\end{array}$

Therefore, the amount spent on lunch $6.

Hence, the correct answer is $6.

Conclusion:

Hence, the correct answer is $6.