Marissa substracted a negative number from a positive number. Her result was negative. Is that reasonable? Explain.
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<h2><u>Correct question</u> : 4x - 3 = 2x + 7 </h2><h2><u>Solution</u> : 4x - 3 = 2x + 7 </h2>
Answer:
- <u>After 1.7 hours</u>
Explanation:
<u>1. Calculate the average speed of train B</u>
- 60mph = 3/4 (s) ⇒ s = 60 (4/3) mph = 80 mph
<u>2. Build a table</u>
When the two trains meet:
Train Average speed Distance time (distance/average speed)
mph
A 60 x x/60
B 80 240 - x (240 - x) / 80
<u>3. Write the equation</u>
The time, when the two trains meet, is the same for both trains:
<u>4. Calculate the time:</u>
- x/60 = 102.86 / 60 = 1.7 hours
The two trains will meet after 1.7 hours