be lit simultaneously so that one candle is twice as long as the other at exactly midnight?
2007-02-23 14:06:46 · 7 answers · asked by wolfwood 2 in Science & Mathematics ➔ Mathematics
9:36pm
2*(3-x)/3=(4-x)/4
Solve, x=2.4 hourse needed to burn
12-2.4=9.6
9.6=9:36pm
2007-02-23 14:21:53 · answer #1 · answered by Anonymous · 3⤊ 1⤋
The answer is 9:36
It can be found with the equation 1-(x/3)*2=1-(x/4)
X= 2.4
This means 2.4 hours before the midnight which is 9:36
The first answer given in this equation showed at what time it should be lit that it takes one candle to burn twice as long(in terms of time). By the way, there will be 20% left in the first candle and 40% in the other
2007-02-23 14:42:23 · answer #2 · answered by Russel 1 · 2⤊ 0⤋
Drake has the correct answer. The candles start out THE SAME LENGTH, so the 3 hr candle is burning 33 1/3% faster than the 4 hr candle.
After 2.4 hours, 80% (i.e. 2.4 / 3) of the 3 hr candle has burned, so 1/5 of the candle is left.
After 2.4 hours, 60% (i.e. 2.4 / 4) of the 4 hr candle has burned, so 2/5 of the candle is left.
Therefore, after 2.4 hours, the 4 hr candle is twice as long as the 3 hr candle, confirming Drake's calculation.
2007-02-23 14:39:22 · answer #3 · answered by Anonymous · 2⤊ 0⤋
enable h be the top of the candle velocity of First Candle = h/4 velocity of 2d Candle = h/3 what proportion hours after being lit replaced into the 1st candle two times the top of the 2d? enable r be the top of the 2d candle at that factor (t). r = h - (h/3)t on a similar time(t), the top of the 1st candle must be 2r 2r = h - (h/4)t 2(h-(h/3)t) = h - (h/4)t 2h - (2/3)ht = h - (a million/4)ht 2-(2/3)t = a million - (a million/4)t t(2/3-a million/4) = a million t = 12/5 hr or 2.4 hr
2016-10-16 08:56:31 · answer #4 · answered by trinkle 4 · 0⤊ 0⤋
at exactly 10 pm this makes the 3 hr candle have an hour left to burn and the 4 hr candle will have 2 hr left to burn
2007-02-23 14:12:43 · answer #5 · answered by ellejare 3 · 3⤊ 1⤋
height of a = original height - t/180(h) : the three hr. candle
height of b = original height - t/240(h) : the four hr. candle
t = time in minutes.
when does b = 2a?
h - t/240(h) = 2*{h-t/180(h)}
height cancels...solve for t....
144 minutes burning meets conditions. or 2:24 hrs.
12-2:24 = 9:36.....I see this could have been simpler...but I like to take the scenic route :)
2007-02-23 14:39:37 · answer #6 · answered by Jennifer B 3 · 2⤊ 0⤋
10:00 O'clock
2007-02-23 14:13:37 · answer #7 · answered by Anonymous · 0⤊ 1⤋