AMC8 2026

AMC8 2026 · Q7

AMC8 2026 · Q7. It mainly tests Fractions, Ratios & proportions.

Mika would like to estimate how far she can ride a new model of electric bike on a fully charged battery. She completed two trips totaling 40 miles. The first trip used $\frac{1}{2}$ of the total battery power, while the second trip used $\frac{3}{10}$ of the total battery power. How many miles can this electric bike go on a fully charged battery?

Mika 想估计一辆新款电动自行车在电池充满电的情况下能骑多远。她完成了两次行程，总计 40 英里。第一次行程使用了总电池电量的 $\frac{1}{2}$，而第二次行程使用了总电池电量的 $\frac{3}{10}$。这辆电动自行车在满电情况下能行驶多少英里？

(A) 45 45

(B) 48 48

(D) 52 52

(E) 55 55

Answer

Correct choice: (C)

正确答案：（C）

Solution

We can see that the total battery spent is $\frac{1}{2}+\frac{3}{10}=\frac{5+3}{10}=\frac{4}{5}$. We can thus write the proportion $\frac{40}{\frac{4}{5}}=\frac{x}{1}$. Since $\frac{40}{\frac{4}{5}}=40\cdot\frac{5}{4}=50$, $\frac{x}{1}=x=(C)\ 50$ miles.

我们可以看到总共消耗的电量是 $\frac{1}{2}+\frac{3}{10}=\frac{5+3}{10}=\frac{4}{5}$。因此我们可以写出比例 $\frac{40}{\frac{4}{5}}=\frac{x}{1}$。由于 $\frac{40}{\frac{4}{5}}=40\cdot\frac{5}{4}=50$，所以 $\frac{x}{1}=x=(C)\ 50$ 英里。

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