QUESTION

CSAT

Easy

Maths

Prelims 2015

The monthly incomes of Peter and Paul are in the ratio of 4:34:3. Their expenses are in the ratio of 3:23:2. If both save Rs. 6000 at the end of the month, their respective monthly incomes are:

Select an option to attempt

Explanation

Given:

Incomes ratio of Peter and Paul = 4:3 Expenses ratio of Peter and Paul = 3:2 Both save Rs. 6,000 at the end of the month

Let: Peter's income = 4x4x Paul's income = 3x3x Peter's expense = 3y3y Paul's expense = 2y2y

Savings Equation: Peter's savings = Income - Expense → 4x3y=6,0004x - 3y = 6,000 Paul's savings = Income - Expense → 3x2y=6,0003x - 2y = 6,000

Solve the system of equations: 4x3y=6,0004x - 3y = 6,000 3x2y=6,0003x - 2y = 6,000

Multiply the second equation by 4 and the first equation by 3: (3x2y)×4(3x - 2y) \times 412x8y=24,00012x - 8y = 24,000 (4x3y)×3(4x - 3y) \times 312x9y=18,00012x - 9y = 18,000

Subtract the second equation from the first: (12x8y)(12x9y)=24,00018,000(12x - 8y) - (12x - 9y) = 24,000 - 18,000 y=6,000y = 6,000

Substitute y = 6,000 in the first equation: 4x3(6,000)=6,0004x - 3(6,000) = 6,000 4x18,000=6,0004x - 18,000 = 6,000 4x=24,0004x = 24,000 x=6,000x = 6,000

Incomes: Peter's income = 4x=4×6,000=4x = 4 \times 6,000 = Rs. 24,000 Paul's income = 3x=3×6,000=3x = 3 \times 6,000 = Rs. 18,000

Answer: Peter's income = Rs. 24,000 Paul's income = Rs. 18,000 Correct Option: A. Rs. 24,000 and Rs. 18,000

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