AMC10 2009 B

AMC10 2009 B · Q3

AMC10 2009 B · Q3. It mainly tests Linear equations, Ratios & proportions.

Paula the painter had just enough paint for 30 identically sized rooms. Unfortunately, on the way to work, three cans of paint fell off her truck, so she had only enough paint for 25 rooms. How many cans of paint did she use for the 25 rooms?

画家Paula原本有刚好足够的油漆刷30间大小相同的房间。不幸的是，在上班路上，三个油漆罐从她的卡车上掉了下来，所以她只够刷25间房间。她刷这25间房间用了多少罐油漆？

(A) 10 10

(B) 12 12

(D) 18 18

(E) 25 25

Answer

Correct choice: (C)

正确答案：（C）

Solution

Answer (C): The loss of 3 cans of paint resulted in 5 fewer rooms being painted, so the ratio of cans of paint to rooms painted is $3:5$. Hence for 25 rooms she would require $\frac{3}{5}\cdot 25 = 15$ cans of paint.

答案（C）：丢失了3罐油漆导致少刷了5个房间，因此油漆罐数与刷漆房间数之比为$3:5$。因此刷25个房间需要$\frac{3}{5}\cdot 25 = 15$罐油漆。

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