SOLUTION: A large watermelon weighs 20kg with 96% of its weight being water. it is allowed to stand in the sun and some of the water evaporates so that only 95% of its weight is water. it's

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: A large watermelon weighs 20kg with 96% of its weight being water. it is allowed to stand in the sun and some of the water evaporates so that only 95% of its weight is water. it's       Log On


   

Question 1087742: A large watermelon weighs 20kg with 96% of its weight being water. it is allowed to stand in the sun and some of the water evaporates so that only 95% of its weight is water. it's reduced weight will be?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Some of the water goes away, but the part that is not water stays.
How much was that part by mass at the start?
It was %22100%25%22-%2296%25%22=%224%25%22=4%2F100=1%2F25=0.04 of the total.
In terms of mass, it was 0.04%2A20kg=0.8kg .
At the end, there were still 0.8kg of stuff that was not water in the shriveled watermelon,
but then it made up %22100%25%22-%2295%25%22=%225%25%22=5%2F100=1%2F20=0.05 of the total.
So the total mass of that shriveled, sun-baked watermelon ended up as
m=20%2A0.8kg=highlight%2816kg%29 or m=0.8kg%2F0.05=highlight%2816kg%29 .
You could say that the final mass, m is such that
%225%25%22=5%2F100=0.05 of it is water;
write 0.05m=0.8kg as an equation,
and "solve for m" to get
m=0.8kg%2F0.05=highlight%2816kg%29 ,
to say you are using algebra.