Fresh grapes contain 80% water by weight and raisins obtained by dryin

Question

Fresh grapes contain 80% water by weight and raisins obtained by drying fresh grapes contain 25% water by weight. How many kgs of fresh grapes are needed to get 20kgs of raisins?
A) 75 kgs
B) 64kgs
C) 72 kgs
D) 65 kgs
E) 70 kgs

Source: 4gmat
Please explain

Bunuel · Accepted Answer

The weight of non-water in 20 kg of dried grapes (which is 100-25=75% of whole weight) will be the same as the weight of non-water in x kg of fresh grapes (which is 100-80=20% of whole weight), so 20*0.75 = x*0.2 --> x = 75.

Answer: A.

ScottTargetTestPrep · Answer

Let x = the number of kilograms of fresh grapes needed to obtain 20 kgs of raisins.

The amount of non-water material in x kgs of fresh grapes is 0.2x. The amount of non-water material in 20 kgs of raisins is 0.75*20 = (3/4)*20 = 15. Since the non-water material remains constant after drying fresh grapes to obtain raisins, we can create the following equation:

0.2x = 15

2x = 150

x = 75

Therefore, 75 kilograms of fresh grapes are needed in order to obtain 20 kgs of raisins after drying.

Answer: A

Bunuel · Answer

Similar questions to practice: each-of-the-cucumbers-in-100-pounds-of-cucumbers-is-composed-102354.html fresh-dates-contain-90-water-while-dry-dates-contain-143245.html five-kilograms-of-oranges-contained-98-of-water-141401.html if-grapes-are-92-water-and-raisins-are-20-water-then-how-159030.html there-are-100-employees-in-a-room-99-are-managers-how-man-171728.html Hope this helps.

Funsho84 · Answer

Used weighted average formula

Wr/Wg= (100 - 80) / (80-25) = 4/11

(4/14) * X = 20

X=75

Answer A

RenB · Answer

KarishmaB  I have often seen you use the weighted average method for questions like these. Could you please share the link to relevant notes made by you or someone else?

I am able to solve these qs using the long methods, but need more efficient methods. TIA!

KarishmaB · Answer

You can check out my YouTube video on weighted average and scale method here: https://youtu.be/_GOAU7moZ2Q The channel is work in progress but this video is up. *Edited the link

RenB · Answer

Found it and subscribed! All the best for your channel!

Ninni1628 · Answer

Hello!

I really had to crack my head to understand how to solve this sum, but for anyone struggling, here's how i understood it. What seems to be a constant in this entire sum is the solid weight of the grapes and the raisins. 1. Fresh Grapes consist of 80% water and 20% solid weight. 2. Raisins consist of 25% water and 75% solid weight. Now we know that to convert grapes into raisins, we need to dry the grapes. In 20 Kgs, 75% would be solid weight, so we can say that 75/100 * 20 = 15kgs So, let the total amount of Fresh Grapes be x Now we need to get 15% of solid content from fresh grapes. Fresh Grapes already have 20% solid in them. 20% of x = 20/100 * x = x/5 So, we can say - equating the solid weight of fresh grapes to raisins, we can set up an equation : x/5 = 15 = 75 kgs

luisdicampo · Answer

Deconstructing the Question

Fresh grapes contain  80% water , so they contain  20% solids . 
Raisins contain  25% water , so they contain  75% solids . 
Drying removes only water, so the mass of  solids stays constant .

Step-by-step

Raisins weigh  20 kg  and are  75% solids , so solids in raisins are: 
 20 	imes 0.75 = 15

Let  x  be the kilograms of fresh grapes. 
Fresh grapes are  20% solids , so solids are  0.20x . 
Solids are conserved, so: 
 0.20x = 15

Solve for  x : 
 x = \frac{15}{0.20}  
 x = 75

Answer: 75 kg

Fresh grapes contain 80% water by weight and raisins obtained by dryin

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Fresh grapes contain 80% water by weight and raisins obtained by dryin

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