On three sunny days the water is evaporated from a potted plant. The first day all but 1/4 of the water is evaporated, the second day leaves 1/5 of the water reaching it. On the third day, 2/3 is evaporated from whats left.
(a) what fraction of water is left in the potted plant after the three days?
(b)what fraction was evaporated?
please show some steps and explaination
2007-09-16 18:01:51 · 5 answers · asked by blah 3 in Education & Reference ➔ Homework Help
After the first day, you have 1/4 of the water.
After the second day, you have 1/5 of that 1/4, or (1/5)*(1/4) = 1/20 of the original water. (General hint: the word "of" usually means "multiply".)
After the third day, you have 1/3 of what was left: (1/3)*(1/20) = 1/60 of what you started with.
Since you have 1/60 left, you must have evaporated 59/60 (discounting what the plant drank).
2007-09-16 18:07:22 · answer #1 · answered by Anonymous · 1⤊ 0⤋
The plant starts out with 100% water
1st day: 1/4 left means 25% left, so 75% (or 3/4) evaporated.
100% - 75% =25% left
2nd day: 1/5 of the 1/4 (or the 25%) left= 1/5 times 25/1 (cancel out the 5 and 25)=5% had evaporated that day, or 80% in 2 days (100% -80% =20%)
3rd day= 2/3 times 1/20 (cancel out the 2 and 20) leaving 1/10 or 10% (90% total in 3 days)
100% - 90%= 10%
90%= 9/10 total evaporation
(Fractions are simply certain percentages of 100, so that is why I showed percents, too)
2007-09-17 01:30:42 · answer #2 · answered by jan51601 7 · 0⤊ 1⤋
It's been a while since high school for my husband but he'll take a stab at it. Here's what he's got:
Day 1-%100 water
all but 1/4 evaporate leaves %25 0r 25/100=1/4
Day 2-%25 water
1/5 of %25 = 25/5=%5
Day 3-5% water
2/3 0f %5= 10/3=%1 2/3 water left
%98 1/3 evaporated
Hope it's right. Like I said, it's been a while.
2007-09-17 01:15:06 · answer #3 · answered by angelina_trimble 1 · 0⤊ 0⤋
It is a trick question inasmuch as the way it is worded. The second day leaves 1/5 of the water 'reaching it' makes no sense. What is meant by 'reaching it'? As far as the problem itself goes, it can be solved quite easily if sensibly phrased. There is a difference between using problem solving skills and phrasing the problem so as to make it impossible to understand the wording.
2007-09-17 01:24:28 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Calculate it.
2007-09-17 01:09:53 · answer #5 · answered by Desert Sienna 4 · 0⤊ 1⤋