4
An individual allocates 1/7th of their income towards travel, 1/3rd of the remaining for food, 1/4th of what's left for rent, and finally, saves 1/6th of the remaining amount, ending up with Rs. 25,000. What is the person's total income?
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Solution: Step 1: Let the total salary = S
Step 2: Travel expenses = S/7, Remaining = 6S/7
Step 3: Food expenses = 1/3 * 6S/7 = 2S/7, Remaining = 6S/7 - 2S/7 = 4S/7
Step 4: Rent expenses = 1/4 * 4S/7 = S/7, Remaining = 4S/7 - S/7 = 3S/7
Step 5: Savings = 1/6 * 3S/7 = S/14, Remaining = 3S/7 - S/14 = 5S/14
Step 6: Given that 5S/14 = 25000
Step 7: Solve for S: S = 25000 * 14 / 5 = 70000
7
Four individuals (A, B, C, and D) collectively buy a gift for Rs. 60. A contributes half of the combined amount paid by B, C, and D. B contributes one-third of the combined amount paid by A, C, and D. C contributes one-fourth of the combined amount paid by A, B, and D. What is the amount D paid?
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Solution: Step 1: Let the amounts paid by A, B, C, and D be A, B, C, and D respectively.
Step 2: The total cost of the gift is Rs. 60. So, A + B + C + D = 60 (Equation 1).
Step 3: Translate the given conditions into equations and solve for A, B, and C:
Condition A: A = (1/2)(B + C + D)
From Equation 1, B + C + D = 60 - A. Substitute: A = (1/2)(60 - A) โ 2A = 60 - A โ 3A = 60 โ A = 20.
Step 4: Condition B: B = (1/3)(A + C + D)
From Equation 1, A + C + D = 60 - B. Substitute: B = (1/3)(60 - B) โ 3B = 60 - B โ 4B = 60 โ B = 15.
Step 5: Condition C: C = (1/4)(A + B + D)
From Equation 1, A + B + D = 60 - C. Substitute: C = (1/4)(60 - C) โ 4C = 60 - C โ 5C = 60 โ C = 12.
Step 6: Now substitute the values of A, B, and C into Equation 1 to find D:
20 + 15 + 12 + D = 60
47 + D = 60
D = 60 - 47
D = 13.
Step 7: The amount paid by D is Rs. 13.