In a store window, there was a box of berries having a total weight of 200 kg. The berries were 99% water, by weight. After two days in the sun, the water content of the berries was only 90%, by weight. What was the total weight of the berries after two days, in kg?
The berries are 99% water, which means that 1% of their weight is not water. Therefore, the weight of the non-water content of the berries is:
0.01 * 200 kg = 2 kg
This means that the weight of the water in the berries is:
200 kg - 2 kg = 198 kg
After two days in the sun, the water content of the berries is 90%, which means that 10% of their weight is not water. Therefore, the weight of the non-water content of the berries is:
0.1 * x = x/10
where x is the total weight of the berries after two days.
This means that the weight of the water in the berries is:
x - x/10 = 9x/10
We know that the weight of the water in the berries has decreased from 198 kg to 9x/10 kg. We can set up an equation to solve for x:
198 kg = (90/99)(9x/10) kg
Simplifying, we get:
19800/90 = (9/10)x
Multiplying both sides by 10/9, we get:
220 = x
Therefore, the total weight of the berries after two days is 220 kg.
So the berries gain 20kgs after two days in the sun.
This might explain the global obesity spate. Exposure to sunshine causes weight gain. Unless we avoid the sun, by year’s end we’re all going to be lard buckets, or bigger lard buckets.
...Macabre, you are well on the way to winnig a Nobel Prize in Physiology.
Stay in touch; some of us will want an autographed photo.
200 kg of berries consist of:
200 * 0.99 =198 kg - water by weight
200 - 198 = 2 kg - berries by weight.
After 2 days drying up in the Sun, we have:
90% of berries by weight is water, and:
10% of berries by weight is fruit.
But 10% of berries by weight =2 kg
Or: 0.10B =2
B=2 / 0.10 = 20 kg - weight of the berries after drying up for 2 days.