[計量] GWD14-11 14-26

[enjoy1221 (恩)]

Mary persuaded n friends to donate 500 each to her election

compaign, and then each of these n friends persuaded n more people to donate

500 each to Mary's compaign.  If no one donated more than once and if there

were no other donations, what was the value of n?

1 THe first n people donated 1/16 of the total amount donated.

2 The total amount donated was 120000

Ans D  我選C耶

If the units digit of the three-digit positive integer k is nonzero, what

is the tens digit of k?

1 The tens digit of k+9 is 3

2 The tens digit of k+4 is 2

Ans A 我覺得第二個也可以

麻煩好心可以幫我一下

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→ GGRIP:n/(n+n^2)=1/(1+n)=1/16,n=15
→ GGRIP:12000/500=240=n+n^2=n(n+1),n=15
→ GGRIP:k+9一定要進位，十位數+1，k+4不一定要進位