AMC10 2012 A

AMC10 2012 A · Q5

AMC10 2012 A · Q5. It mainly tests Fractions, Basic counting (rules of product/sum).

Last year 100 adult cats, half of whom were female, were brought into the Smallville Animal Shelter. Half of the adult female cats were accompanied by a litter of kittens. The average number of kittens per litter was 4. What was the total number of cats and kittens received by the shelter last year?

去年，有100只成年猫被带到Smallville动物收容所，其中一半是母猫。成年母猫中有一半带着一窝小猫。每窝小猫的平均数量是4。去年收容所收到的猫和小猫总数是多少？

(A) 150 150

(B) 200 200

(D) 300 300

(E) 400 400

Answer

Correct choice: (B)

正确答案：（B）

Solution

The number of female adult cats was 50, and 25 of those were accompanied by an average of 4 kittens each. Thus the total number of kittens was $25 \cdot 4 = 100$, and the total number of cats and kittens was $100 + 100 = 200$.

成年母猫的数量是50，其中25只带着平均每窝4只小猫。因此小猫总数是$25 \cdot 4 = 100$，猫和小猫总数是$100 + 100 = 200$。

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