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
You can set this up as 2 fractions equal to each other, like ratios.
18/11=108/x
Cross multiply and you get 18x=1,188
Now divide both sides by 18 and get x.
x=66.
If the height of the building is 108ft, the width is 66ft.
Answer:
Step-by-step explanation:
If y = 2x + 1, then dy/dt = 2(dx/dt).
If y = 2x + 1, then y = 2(40) + 1 when 40 is substituted for x. y = 81.
(a) if dx/dt = 3, find dy/dt when x = 4:
Replacing dx/dt with 3 in dy/dt = 2(dx/dt) yields dy/dt = 2(3) = 6.
(b) if dy/dt = 2, find dx/dt when x = 40:
Replacing dy/dt with 2 in dy/dt = 2(dx/dt) results in 2 = 2(dx/dt), so dx/dt must be 1.
Step-by-step explanation:
The Alps were born 770 million years ago.
Hope this helps..
