RBI Grade B Officers 2017 jun Paper

(3) Case I.
Liquid A ⇒ 7x litresLiquid B ⇒ 5x litresIn 9 litres of mixture,
Liquid A=

7

12

×9=

21

4

litres
Liquid B =

5

12

×9=

15

4

litres
According to the question,
7x−

21 4

5x− 15 4 +9

=

7

9

⇒

28x−21

20x−15+36

=

7

9

⇒

28x−21

20x+21

=

7

9

⇒

4x−3

20x+21

=

1

9

⇒ 36x – 27 = 20x +21
⇒36x–20x=27+21
⇒16x=48
⇒x=

48

16

=3
∴ Initial quantity of liquid A
= 7x
= 21 litres.