PP-T1-PS81

[Huang Hsin-Yi]

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

[Huang Hsin-Yi]

查到答案了

設有a個7,b個77

7a+77b=350 a+11b=50
數字代入
b=1, a=39

n=40

這種題目真讓人哭笑不得