Problem 6 · 1993 AJHSME
Medium
Ratios, Rates & Proportions
unit-rate
A can of soup can feed 3 adults or 5 children. If there are 5 cans of soup and 15 children are fed, then how many adults would the remaining soup feed?
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Answer: B — 6 adults.
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Hint 1 of 2
The cans get spent in two jobs: first feeding the kids, then feeding adults with whatever's left. So figure out the kids' share of cans before anything else.
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Hint 2 of 2
A can is a fixed 'unit' here — one can feeds 5 children OR 3 adults. Convert children-to-cans, subtract, then convert leftover-cans-to-adults.
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Approach: spend cans on children first, convert the leftovers
- Each can feeds 5 children, so 15 children eat exactly 15 ÷ 5 = 3 cans. That leaves 5 − 3 = 2 cans untouched.
- Each leftover can feeds 3 adults, so 2 cans feed 2 × 3 = 6 adults.
- Watch the trap: the can is the currency, not the person. Don't try to convert children straight into adults (a can isn't '5 children = 3 adults' once it's been opened) — count whole cans used, then refill the rest with adults.
Mark:
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