# Lesson 6

Distinguishing between Two Types of Situations

Let’s think about equations with and without parentheses and the kinds of situations they describe.

### Problem 1

A school ordered 3 large boxes of board markers. After giving 15 markers to each of 3 teachers, there were 90 markers left. The diagram represents the situation. How many markers were originally in each box?

(From Unit 6, Lesson 2.)

### Problem 2

The diagram can be represented by the equation $$25=2+6x$$. Explain where you can see the 6 in the diagram.

(From Unit 6, Lesson 3.)

### Problem 3

Match each equation to a story. (Two of the stories match the same equation.)

1. $$3(x+5)=17$$
2. $$3x+5=17$$
3. $$5(x+3)=17$$
4. $$5x+3=17$$
1. Jada’s teacher fills a travel bag with 5 copies of a textbook. The weight of the bag and books is 17 pounds. The empty travel bag weighs 3 pounds. How much does each book weigh?
2. A piece of scenery for the school play is in the shape of a 5-foot-long rectangle. The designer decides to increase the length. There will be 3 identical rectangles with a total length of 17 feet. By how much did the designer increase the length of each rectangle?
3. Elena spends $17 and buys a$3 book and a bookmark for each of her 5 cousins. How much does each bookmark cost?
4. Noah packs up bags at the food pantry to deliver to families. He packs 5 bags that weigh a total of 17 pounds. Each bag contains 3 pounds of groceries and a packet of papers with health-related information. How much does each packet of papers weigh?
5. Andre has 3 times as many pencils as Noah and 5 pens. He has 17 pens and pencils all together. How many pencils does Noah have?

### Problem 4

Elena walked 20 minutes more than Lin. Jada walked twice as long as Elena. Jada walked for 90 minutes. The equation $$2(x+20)=90$$ describes this situation. Match each expression with the statement in the story with the expression it represents.