Store A sells apples at $3 per kg and oranges at $4 per kg. A customer spent $24 on a total of 7 kg of apples and oranges. How many kg of apples did the customer buy?
A3
B4
C5
D6
Answer & Solution
Correct answer: B. 4
Let a = kg of apples, o = kg of oranges. Then a + o = 7 and 3a + 4o = 24. From first: o = 7 - a. Substitute: 3a + 4(7 - a) = 24 → 3a + 28 - 4a = 24 → -a = -4 → a = 4. So 4 kg of apples (and 3 kg of oranges; check: 3(4) + 4(3) = 12 + 12 = 24 ✓).
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