PP-PS-T1-81

[sunnyblue13s]

81. 9215-!-item-!-187;#058&006304
If each term in the sum a1 + a2 + . . . + an is either 7 or 77 and the sum equals 350, which of the following could be equal to n ?

(A) 38
(B) 39
(C) 40
(D) 41
(E) 42

ANS:C

請麻煩幫幫我....我真的看不懂這題到底想要幹麻....

[Huang Hsin-Yi]

設7有a個,77有b個

7a+77b=350
a+11b=50

當b=1,a=39

1+39=40

[sunnyblue13s]

很謝謝你的協助~~:)

[queentypei]

當初我就是被他If each term "in the sum"給搞迷糊了
如果照前面大大的解法，題目是指每個term不是7就是77嗎??

謝謝回答囉。^^

[larry.tw]

沒錯看起來是這樣的意思！！