有几道GMAT数学题弄不懂,1、If 1050（是10的50次方） – 74 is written as an integer in base 10 notation,what is the sum of the digits in that integer?2、If x > 0,then 1/[√(2x)+√x] =3、A positive integer n is said to be “prime-saturated” if the product of all the different positive prime factors of n is less than the square root of n.What is the greatest two-digit prime-saturated integer?A,99 B,98 C,97 D,96 E,95
问题描述：
有几道GMAT数学题弄不懂,
1、If 1050（是10的50次方） – 74 is written as an integer in base 10 notation,what is the sum of the digits in that integer?
2、If x > 0,then 1/[√(2x)+√x] =
3、A positive integer n is said to be “prime-saturated” if the product of all the different positive prime factors of n is less than the square root of n.What is the greatest two-digit prime-saturated integer?
A,99 B,98 C,97 D,96 E,95
答
1.The answer is 440
1000...000
- 74
-------------
999...926
So it's 9*48+2+6=432+8=440
2.It could also be written as (√(2x)-√x)/x.
3.The answer is D.
"prime-saturated" is (product of all different prime factor) A.99=3*3*11,33>10,not fit
B.98=2*7*7,14>10,not fit
C.97 is prime number,definitly not fit
D.96=3*2*2*2*2*2,610,not fit