⟩ Suppose You spend 21 dollars on vegetables at the store. You buy carrots, onions and celery. The celery cost half the cost of the onions. The onions cost have the cost of the carrots. How much did the onions cost?
Answering this problem just requires some simple algebra. If we assume the cost of celery = x, then the cost of onions = 2x, and cost of the carrots is 4x, such that the total cost of all vegetables = x + 2x + 4x = 7x = 21 dollars. Consequently, x = 3 dollars. Hence, the onions cost 6 dollars.
