A person has to buy both apples and mangoes. The cost of one apple is ₹ 7/-…

Concept — When two kinds of items with fixed unit prices are bought together, the money spent is (unit price of the first item × its count) + (unit price of the second item × its count), and that total cannot exceed the budget. Counts of physical items are whole numbers, and a requirement to buy both kinds forces each count to be at least 1. A budget statement on its own leaves several counts affordable, so a question of this form pins down a single count only under a further standard condition: either (i) the whole budget is used up, or (ii) the item being asked about is taken as large as the budget allows. When both conditions lead to the same count, that count is the answer whichever reading is intended.

Application — Let a be the number of apples and m the number of mangoes. Both are whole numbers with a ≥ 1 and m ≥ 1 because both fruits must be bought, and the budget gives 7a + 5m ≤ 38.

1. Reading (i), in which the whole ₹ 38 is used, turns the inequality into the equation 7a + 5m = 38.

2. Rearranging, 5m = 38 − 7a, hence m = (38 − 7a)/5, which is a whole number only when 38 − 7a is a positive multiple of 5.

3. Only a = 1 to 5 need testing, because a = 6 already costs 7 × 6 = 42, which is more than ₹ 38.

Reading (ii), the largest number of apples that still leaves enough for at least one mango, gives 7a + 5 ≤ 38, so 7a ≤ 33 and a ≤ 4.71; since a is a whole number, a = 4.

Cross-check — Both readings give a = 4, so the count the question asks for does not depend on which disambiguation is intended, and 4 is the officially keyed answer for this paper. Substituting back into reading (i): 4 × ₹ 7 + 2 × ₹ 5 = ₹ 28 + ₹ 10 = ₹ 38, exactly the money available, with both fruits bought. A last-digit argument confirms that reading (i) has no other solution: 38 − 7a ends in 0 or 5 only when 7a ends in 8 or 3, and among 7, 14, 21, 28 and 35 only 28 qualifies. Reading (ii) on its own fixes only the apple count and not the mango count, because the ₹ 10 left over would buy either one or two mangoes; the apple count is what the question asks for.

Result — The number of apples is 4; under the full-expenditure reading the purchase is 4 apples together with 2 mangoes.