OG(11th)PS-Q91

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請問一下...可能是小弟愚昧

題目說
If sam were twice as old as he is, he would be 40 years older than Jim. If Jim is 10 years younger than Sam, How old is Sam?

依題意我列出來的式子如下
S=2h
h=J+40
S=J+10

可是我看OG的解答
第一式是
2S=J+40

就我看來sam were twice as old as he is
指的是Sam的年紀是he的兩倍
但OG的式子是he是Sam的兩倍

是我這句解讀錯了嗎？
為此check過了36題、文法書，跟其它類似的文章
似乎我的解讀沒有錯

還是其它的問題呢(那個假設語氣)？

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orz....
post上來後
我好像突然看懂了(好像不能刪post)....或許傷咖有神奇的魔力

原來那個he指的是sam
所以原句是說如果sam的年紀是他原來的兩倍....