GeminiHeat wrote:
On January 1, 2076, Lake Loser contains x liters of water. By Dec 31 of that same year, 2/7 of the x liters have evaporated. This pattern continues such that by the end of each subsequent year the lake has lost 2/7 of the water that it contained at the beginning of that year. During which year will the water in the lake be reduced to less than 1/4 of the original x liters?
A. 2077
B. 2078
C. 2079
D. 2080
E. 2081
Since
27th of the water evaporates, we will be left with
57th of water at the end of year
On 1 Jan 2076 =
x litres
On 31 Dec 2076 =
57x=0.71x litres
On 31 Dec 2077 =
(57)2x=0.51x litres
On 31 Dec 2078 =
(57)3x=0.36x litres
On 31 Dec 2079 =
(57)4x=0.26x litres
On 31 Dec 2080 =
(57)5x=0.18x litres
Hence, option D