Question

GRADE 8 UNIT 5 LESSON 5 OPEN UP RESOURCES

Answer 1

a. It spends 2.04 hours going 55 mph.

b. It will spend 1 hour going 35 mph.

c. The trip will take 3.64 hours.

Step-by-step explanation:

Given equation is;

55x + 35y = 200

Where

x represent the time when speed is 55 mph

y represent the time when speed is 35 mph

a. If the car spends 2.5 hours going 35mph on the trip, how long does it spend going 55mph?

Putting y=2.5 in given equation

$55x+35(2.5)=200\\55x+87.5=200\\55x=200-87.5\\55x=112.5$

Dividing both sides by 55

$\frac{55x}{55}=\frac{112.5}{55}\\x=2.04\ hours$

It spends 2.04 hours going 55 mph.

b. If the car spends 3 hours going 55mph on the trip, how long does it spend going 35mph?

Putting x=3 in given equation

$55(3)+35y=200\\165+35y=200\\35y=200-165\\35y=35$

Dividing both sides by 35

$\frac{35y}{35}=\frac{35}{35}\\y=1$

It will spend 1 hour going 35 mph.

c. If the car spends no time going 35mph, how long would the trip take?

Putting y=0 in given equation

$55x+35(0) = 200 \\55x+0=200\\55x=200$

Dividing both sides by 55

$\frac{55x}{55}=\frac{200}{55}\\x=3.636$

Rounding off

x = 3.64

The trip will take 3.64 hours

Keywords: linear equation, division

Learn more about linear equations at:

• brainly.com/question/5282516
• brainly.com/question/5424148

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