Shortcut Trick
Equating the initial and new ratios for liquids A and B: (2x + 6) ÷ (3x + 12) = 3 ÷ 5 ⇒ 10x + 30 = 9x + 36 ⇒ x = 6.
New quantity of A = 2(6) + 6 = 18 liters (which represents 3 parts of the new ratio).
Since 3 parts = 18 liters, 1 part = 6 liters, and new C (8 parts) = 8 × 6 = 48 liters.
Initial quantity of C = 5x = 5(6) = 30 liters.
Quantity of C added = Final C − Initial C = 48 − 30 = 18 liters.
∴ The correct answer is 18 liters.
Alternate Method
Given:
Initial ratio of A, B, and C = 2 : 3 : 5
Quantity added to A = 6 liters
Quantity added to B = 12 liters
New ratio of A, B, and C = 3 : 5 : 8
Formula Used:
New Quantity = Initial Quantity + Quantity Added
Liquid A2x → 12 L+ 6 L18 L (3 parts)Liquid B3x → 18 L+ 12 L30 L (5 parts)Liquid C5x → 30 L+ y L48 L (8 parts)Initial Ratio = 2 : 3 : 5y = 48 − 30 = 18 Liters
Calculations:
⇒ Let the initial quantities of A, B, and C be 2x, 3x, and 5x respectively.
⇒ After adding 6 liters to A and 12 liters to B, their respective new quantities are:
⇒ New A = 2x + 6
⇒ New B = 3x + 12
⇒ According to the new given ratio of A to B (3 : 5), we can set up the equation:
⇒ (2x + 6) ÷ (3x + 12) = 3 ÷ 5
⇒ 5 × (2x + 6) = 3 × (3x + 12)
⇒ 10x + 30 = 9x + 36
⇒ 10x − 9x = 36 − 30
⇒ x = 6
⇒ Initial quantity of C = 5x = 5 × 6 = 30 liters
⇒ New quantity of A = 2(6) + 6 = 12 + 6 = 18 liters
⇒ According to the new ratio (3 : 5 : 8), 3 parts correspond to 18 liters of liquid A.
⇒ 1 part = 18 ÷ 3 = 6 liters
⇒ The new quantity of C corresponds to 8 parts of this ratio.
⇒ New C = 8 × 6 = 48 liters
⇒ Quantity of C added = New quantity of C − Initial quantity of C
⇒ Quantity of C added = 48 − 30 = 18 liters
∴ The correct answer is 18 liters.
Additional Information
Ratio Multiplier Concept
When components of a mixture are given in a ratio a : b : c, their absolute quantities can be modeled as ax, bx, and cx where x acts as a common variable multiplier.
Handling Independent Alterations
When distinct amounts are added to specific mixture components, forming an equation using only the known ratio components will yield the multiplier first, before trying to evaluate the unknown variables.
Cross-Multiplication Method
For simple rational equations structured as a ÷ b = c ÷ d, you can quickly simplify and solve by using direct cross-multiplication: a × d = b × c.