IBPS SO Prelims Exam Model Paper 5

Given:
Initial ratio = 2: 3
Final quantity = 10% acid + 90% water
Capacity of glass = 100 ml
Process repeated = 2
Formula used:
Final Q = Initial Q × (1−(

volume‌removed

Initial‌Q

)n
Here, n = Number of times volume taken out
Calculation:
Initial quantity of acid = (

2

5

) × 100
⇒ Initial quantity of acid = 40
⇒ Final quantity = 0.10 × 100
⇒ Final quantity = 10 ml
Now,
10 = 40 × (1 – (

X

40

)2
⇒ 10 = 40 × (

(40–X)

40

)2
⇒ 400 = (40–X)2
⇒ 20 = 40 – X
⇒ X = 20
∴ 20 ml of mixture was replaced twice with acid