Question 72452: An earthquake in Los Angeles surfaced an unearthly creature that had been trapped underground for centuries. It came to life and ate every plant in its path, causing it to grow out of control. Each day it doubled in volume. At 8 a.m. on January 14th, it was seen by fishermen who estimated its size to be a blob of about 100 cubic feet. For five days it grew and nothing could stop it. Finally, on January 19th, it fell into the Pacific Ocean and drowned. How big was it when it died?
Found 2 solutions by jim_thompson5910, psbhowmick:
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! If it was 100 cubic feet on the 14th, then it doubles to 200 cubic feet on the 15th. This sequence is in this order:
100,200,400,800,1600,3200
So on the 19th it is 3200 cubic feet
Answer by psbhowmick(878)  (Show Source):
You can put this solution on YOUR website! On 14th Jan, 8 am the size of the creature was 100 cu ft.
It doubles its size in each day.
It dies on 19th (8 am, assumed).
So we have to find how much its size increased in 5 days.
On 15th its size = 200 cu ft.
On 16th its size = 400 cu ft.
On 17th its size = 800 cu ft.
On 18th its size = 1600 cu ft.
On 19th its size = 3200 cu ft.
Thus the size of the creature was 3200 cubic feet when it died.
Remark: This problem could also have been solved by G.P. series method.
|
|
|
