Problema Solution
99% of the mass of a watermelon is water. After the watermelon was lying in the sun it dried up some, and now contains only 98% water. By how many percent has the total mass of the watermelon decreased?
Answer provided by our tutors
let
x = the original total mass of the watermelon
x = 99% water + 1 % dry matter
x = 0.99*x + 0.01*x
the new weight 'y' is
y = 0.98*x + 0.01*x
((x - y) / x) * 100 =
= ( x(0.99 - 0.98) + 0.01*x - 0.01*x)/ (0.99*x + 0.01*x) =
= 0.01*x / x = 0.01
the percentage is 0.01*100 % = 1%
The total mass of the watermelon deceased by 1%.