AlgebraVery hardCoffees sold from two days' takings
Algebra practice question
A café sells coffee for $3 a cup and tea for $2 a cup. On Monday its takings from these drinks were $260. On Tuesday it sold the same number of coffees as on Monday but twice as many teas, and its takings were $340. How many coffees did the café sell on Monday?
Answer: 60
With c coffees and t teas on Monday: 3c + 2t = 260 and 3c + 4t = 340. Subtracting gives 2t = 80, so t = 40 and 3c = 180, c = 60.
Common wrong answers
- If you answered 40
- 40 is the number of teas on Monday.
- If you answered 80
- 80 is the number of teas on Tuesday.
- If you answered 86.67
- 86.67 divides 260 by 3, ignoring the teas.
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