Correct Answer - Option 4 : 8 : 6 : 7

**Given:**

30% of water from bucket a is added to bucket b

Hence the water in the bucket b increases by 40%

Final ratio of water in the buckets a and c = 8 : 7

**Formula Used:**

If the volume of a quantity increase by x%,

New Quantity = [(100 + x)/100] × Initial Quantity

**Calculation:**

We are adding 30% of the quantity from the bucket a into bucket b and the quantity in bucket b increases by 40%,

⇒ [(30/100) × a] + b = [(100 + 40)/100] × b

⇒ 0.3a + b = 1.4 b

⇒ 0.3a = 0.4 b

Hence, a : b = 4 : 3

Now, a : b = 4 : 3 and a : c = 8 : 7

Also, to equate the two ratios, we can multiply the two parts of the ratio of a and b by 2 as:

a : b = (4 × 2) ∶ (3 × 2) = 8 ∶ 6

∴ a : b : c = 8 : 6 : 7