Answer:
- 1.25 hours or 1 hour and 15 minutes
Step-by-step explanation:
<em>Question</em>
- <em>Lisa lit a candle with a height of 8 inches. When lit, this candle loses 10% of its original height every hour. </em>
- <em>Please complete the following sentence by writing the number in the blank.
Until the candle has been burning for at least _______ hours, the height of Jennifer's candle will be more than 7 inches.</em>
<u>Candle looses 10% of 8 inches, it equals:</u>
- 8*0.1 = 0.8 inches an hour
<u>Let x be required time, then:</u>
- 8 - 0.8x > 7
- 0.8x < 8 - 7
- 0.8x < 1
- x < 1/0.8
- x < 1.25
- or 1 hour 15 minutes
Answer:
B. subtraction property of inequality
Step-by-step explanation:
Assume that the rule connecting height of the candle to time is a linear one. If you do, then we have to find the equation of this line, and then use this equation to predict the height of the candle after 11 hours.
Two points on this line are (6,17.4) and (23, 7.2). The slope is thus
7.2-17.4 -6
m = --------------- = ----------- or -3/5.
23-6 10
Find the equation of the line. I'm going to use the slope-intercept formula:
y = mx + b => 7.2 = (-3/5)(23) + b. Solving for b, b = 21.
Now we know that y = (-3/5)x + 21
Let x=11 to predict the height of the candle at that time.
y = (-3/5)(11) + 21 = 14.4 inches (answer)
