AMC8 2000

AMC8 2000 · Q10

AMC8 2000 · Q10. It mainly tests Percent, Interest / growth (simple).

Ara and Shea were once the same height. Since then Shea has grown 20% while Ara has grown half as many inches as Shea. Shea is now 60 inches tall. How tall, in inches, is Ara now?

Ara 和 Shea 曾经身高相同。此后 Shea 长高了 20%，而 Ara 长高了 Shea 英寸数的一半。Shea 现在 60 英寸高。Ara 现在多高（英寸）？

(A) 48 48

(B) 51 51

(D) 54 54

(E) 55 55

Answer

Correct choice: (E)

正确答案：（E）

Solution

Answer (E): Shea is 60 inches tall. This is 1.2 times the common starting height, so the starting height was $\frac{60}{1.2}=50$ inches. Shea has grown $60-50=10$ inches. Therefore, Ara grew 5 inches and is now 55 inches tall.

答案（E）：Shea 现在身高 60 英寸。这是共同起始身高的 1.2 倍，因此起始身高为 $\frac{60}{1.2}=50$ 英寸。Shea 增长了 $60-50=10$ 英寸。因此，Ara 增长了 5 英寸，现在身高 55 英寸。

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