1.in planning for a trip,joan estimated both the distance of the trip,and her average speed,in miles per hour.she accurately divided her estimated distance by her estimated average speed to obtain an estimated for the time,in hours,that the trip would take.was her estimate within 0.5hour of the actual time that the trip took?1)joan's estimate for the distance was within 5 miles of the actual distance. 2)joan's estimate for her average speed was within 10 miles per hour of her actual average speed 为什么选e?
2what is the remainder when the positive integer n is divided by the positive integer k,where k>1? 1)n=(k+1)3次方 2)k=5 为什么选a
3the average of a list of numbers is what percent of the sum of the numbers? 1)there are 8 numbers in the list 2)the sum of the numbers in the list is 100 为什么选a
4. 2x+y=12 绝对值y=12 for how many ordered pairs(x,y)that 2 solutions of the system above are x and y both integers? a.7 b.10 c.12 d.13 e.14 为什么选d
5.one gram of a certain health food contains 7percent of the minimum daily requirement of vitamin e and 3 percent of the minimum daily requirement of vitamin A.if vitamins E and A are to be obtained from no other source,approximately how many grams of the health food must be eaten daily to provide at least the minimum daily requirement of both vitamins? a.3 b.7 c.10 d.14 e.33 为什么选e阿
6.what is the remainder when the two digit,positive integer x is divided by 3 1)the sum of the digits of x is 5 2)the remainder when x is divided by 9 is 5 为什么选d 阿
7.in town x,64percent of the population are employed,and 48percent of the population are employed males,what percent of the employed people in town x are females? 为什么是25%?