求助两道数学题

michaelzhao007UID: 2195708

If a and b are intergers such that a+b<1000 and A/B=0.625.what is the greatest possible value of b?
1 `+ L# I* \2 D; D& u答案是６０８，我怎么算都是６１５．求助高人啊．
+ y, I" L5 u7 u& l8 d
! s; v; H4 m* x2 }* X9 f  d: F& c7 u
, n1 W8 u: r1 f0 t- A% p* L& H2 pHow amy positive intergers less than 1000 are mutiples of 5 and are equal to 3 times an even interger?

amyceresUID: 2206721

615*0.625不是整数啊，a b都是整数
% b9 u) j  d+ A7 r' \第二道我觉得应该是30 60 90 120 150……990

einsteiniiUID: 2252184

板凳

suimongUID: 2256015

原帖由 amyceres 于 2006-10-5 20:50 发表
615*0.625不是整数啊，a b都是整数
第二道我觉得应该是30 60 90 120 150……990

同意。

powerpycUID: 2180236

老实说,第2题没看懂,那个"are equal to 3 times an even interger"是什么意思哟

qiuwanyingUID: 2198063

原帖由 powerpyc 于 2006-10-6 18:54 发表
老实说,第2题没看懂,那个"are equal to 3 times an even interger"是什么意思哟

“等于3乘以一个偶数”

michaelzhao007UID: 2195708

第2题答案是33个.很纳闷啊..

amyceresUID: 2206721

are equal to 3 times an even interger你理解成是3的倍数的一个偶数就可以解决了

water0915UID: 2222422

1.If a and b are intergers such that a+b<1000 and A/B=0.625.what is the greatest possible value of b?
5 k5 g+ U0 U5 j% Y( ^  p2 j
1.625x<1000
x<615.358

0.625 = 5/8

x= multiple of 8
' o7 I, C2 a) U4 o7 y2 G( q
* L5 R+ o0 H1 k7 n" [# g7 kcount down 615 to find the nearest multiple of 8, then we got 608
6 P7 w9 j1 F0 f6 S. }1 M* M) F

  j  [9 o/ P$ g. h% f/ q; A2.How amy positive intergers less than 1000 are mutiples of 5 and are equal to 3 times an even interger?
9 P# u: O' ?8 W
even no. = 2x
. c1 ]' x4 e/ Q- l: D* [6 _& S
3*(2x)=6x

nos are multiple of 6 and 5 which is 30.

1000/30 = 33