Maths for smart guys

1. 
A, B and C are digits of nubers. A+B=C. AB, multiplied by X, is ACB. What is the amount of X? 

7
9
10
11

2. 
If the sum of A and B is constant, when A*B is bigger? 

When the difference between A and B is smaller
When the difference between A and B is bigger
no matter
it can not be solved

3. 
Which is the next number in the order: 6, 10, 19, 34... 

53
60
66
69

4. 
If there are 9 boxes, How many balls at least should be there in all boxes to make sure that in one of them there are 6 balls? 

6
9
46
54
666
no true answer

5. 
Which statement is NOT always true? 

A+B=B+A
A*B=B*A
A^B=B^A
all are true

6. 
A can divided into B. And X can be divided into A. Is it for sure that X can be divided into B? 

Yes
No

7. 
A and B are bigger than C and D. Is it for sure that A*B is bigger than C*D? 

Yes
No

8. 
If 7 out of 10 people have been to Asia and 7 out of ten have been to Africa, how many people have been to both Asia and Africa for sure? 

at least 4
at least 6
at least 7

9. 
Which span is longer? 

thousand days
3 years

