Cindy bought 15 apples and 12 oranges and paid a sum of ₹447 for the purchase. Which of the statements given below is inconsistent with the information given in the previous statement, leading to no possible prices of the two fruits?
- (a)Purchased 10 apples and 13 oranges and paid a sum of ₹353
- (b)Purchased 25 apples and 20 oranges and paid a sum of ₹745
- (c)Purchased 35 apples and 28 oranges and paid a sum of ₹1,029
- (d)Purchased 12 apples and 8 oranges and paid a sum of ₹340
Answer
Why
Correct — C. Reduce the purchase to one equation and test each statement against it.
Let an apple cost ₹x and an orange ₹y.
15x + 12y = 447, and dividing by 3 gives 5x + 4y = 149.
Option (c) says 35x + 28y = 1029. Dividing by 7 gives 5x + 4y = 147.
The same left-hand side cannot be 149 and 147 at once, so option (c) admits no prices at all — it is the inconsistent statement.
Why the others are wrong
- (a)Purchased 10 apples and 13 oranges and paid a sum of ₹353 — Consistent. Solved with 5x + 4y = 149, the statement 10x + 13y = 353 gives x = 21, y = 11 — real, positive prices, so nothing is contradicted.
- (b)Purchased 25 apples and 20 oranges and paid a sum of ₹745 — Consistent. 25x + 20y = 745 divides by 5 to 5x + 4y = 149, the stem restated. It adds no information, but it rules nothing out either.
- (d)Purchased 12 apples and 8 oranges and paid a sum of ₹340 — Consistent. 12x + 8y = 340 divides by 4 to 3x + 2y = 85, which x = 21, y = 11 satisfies, since 63 + 22 = 85.
Concept
Two linear equations in two unknowns are inconsistent when their left sides are proportional and their constants are not — parallel lines that never meet.
Here 15x + 12y and 35x + 28y are both multiples of 5x + 4y, at 3 times and 7 times. The totals must therefore stand in the same 3:7 ratio.
447 × 7 ÷ 3 = 1043. So 35 apples and 28 oranges cost ₹1,043, and ₹1,029 is impossible whatever the two prices are.
The other three statements are all satisfied by x = 21 and y = 11, so the question is not which prices look right. It is which statement cannot be true at all.
Key facts
- 15x + 12y = 447 reduces to 5x + 4y = 149 on dividing by 3.
- Prices of ₹21 an apple and ₹11 an orange satisfy the stem and options (a), (b) and (d).
- 35 apples and 28 oranges must cost 447 × 7 ÷ 3 = ₹1,043, so ₹1,029 cannot occur.
- A pair of equations with proportional left sides and a non-proportional constant has no solution.
Study next
Common traps
- Solving all four options in full instead of scaling the stem equation once.
- Calling option (b) wrong because it yields no unique prices — it is consistent, merely redundant.
- Assuming the prices must be whole rupees. The test is consistency, not integrality.
SSC dresses a solvability condition as a shopping story, so the work is algebraic rather than arithmetic: reduce the stem to lowest terms and test each option against it. The scaling is the shortcut, since 15:12 and 35:28 both reduce to 5:4.
Related PYQs
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