继续求教纠结的数学题！prep上的

happylxm

1.when positive integer n is divided by 3, the remainder is 2; and when positive integer t is divided by 5, the remainder is 3. What is the remainder when the product nt is divided by 15?
(1) n-2 is divisible by5
(2) t is divisible by3
答案是C
2. equilateral triangle ABC is inscribed in the circle. If the length of arcABC is 24, what is the approximate diameter of the circle?
5? 8? 11? 15? 19?
我在8和11中纠结，16/3倍根3 再怎么约也不可能等于11啊……答案是11

3. a used-car dealer sold one car at a profit of 25 percent of the dealer's purchase price that car and sold another car at a loss of 20 percent of the dealer's purchase price for that car. If the dealer sold each car for $20,000, what was the dealer's total profit of loss, in dollars, for the two transactions combined?
$1,000 profit
$2,000 profit
&1,000 loss
$ 2,000 loss
$3,334 loss
答案C，why loss?难道不是(25%-20%)*20,000?

4.A contractor combined x tons of a gravel mixture that contained 10 percent gravel G, by weight, with y tons of a mixture that contained 2 percent gravel G, by weight, to produce z tons of a mixture that was 5 percent gravel G, by weight. What is the value of x?
(1)y=10
(2)z=16
答案D~how come?

happylxm

第二个和第三个能再详细讲一下不~~感谢！

alannesta

楼主2题你理解错了吧，等边三角形内切(inscribed)于一个圆中，弧ABC长为24，圆的周长就是36啊，然后求直径。。

hsuyinfeng

第三题  百分之二十五的利润  所以购买价是 1600 刀  亏损百分之二十  所以购买价是 2500刀  两车总共买入价为4100  但是卖出价只有4000刀 所以亏损 1000刀

happylxm

恩恩~~got it!! arc我给理解错了~

happylxm

谢啦！！明白了！主要还是读题问题！