GMAT CLUB OLYMPICS: In the image above, if the area of the blue rectan

Question

https://gmatclub.com/forum/download/file.php?id=62925 In the image above, if the area of the blue rectangle is 20 cm^2 and the area of the green rectangle is 25 cm^2, then what is the are of the yellow rectangle ? A. 9 cm^2 B. 12 cm^2 C. 15 cm^2 D. 18 cm^2 E. 21 cm^2 M37-21 Untitled16.png

Bunuel · Accepted Answer

Official Solution:

https://gmatclub.com/tests-beta/resources/import/img/M37-21.png 
 
In the image above, if the area of the blue rectangle is  20 \ cm^2  and the area of the green rectangle is  25 \ cm^2 , then what is the are of the yellow rectangle ?

A.  9 \ cm^2 
B.  12 \ cm^2 
C.  15 \ cm^2 
D.  18 \ cm^2 
E.  21 \ cm^2

https://gmatclub.com/tests-beta/resources/import/img/M37-21-2.png 
 
Let the width and the length of the yellow rectangle be  x  and  y  cm, respectively.
 
Then we'd hqave:
 
(i)  Area_{blue}=(7-x)y=7y-xy=20 
 
(ii)  Area_{green}=(8-x)y=8y-xy=25 
 
Subtract (i) from (ii) to get  y=5 . 
 
Substitute  y=5  into (i) to get  x=3 . 
 
 Area_{yellow}=xy=15

Answer: C

avinashiitp · Answer

On the basis of below figure, (7-x)y=20 (1) (8-x)y=25 (2) solve 1 and 2 get x=3, y=5 Hence xy=15 And C Img.JPG

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