Subject :IMO Class : Class 6
Find the missing number, if same rule is followed row-wise or column - wise. 
A15
B18
C20
D25
Ans 1:
Class : Class 6
option d is the correct answer .r
Ans 2:
Class : Class 9
Ans 3:
Class : Class 6
Ans 4:
Class : Class 8
OPTION D.FIRST WE HAVE TO DIVIDE THE FIRST AND LAST NUMBERS IN ONE COLUMN ,IF WE TAKE THE FIRST COLUMN THE FIRST NUMBER IS 28 AND THIRD NUMBER IS 14. 28 DIVIDED BY 14 IS EQUAL TO 2. THIS 2 IS OBTAINED BY DIVIDING THE MIDDLE NUMBER 10 WITH 5. IN THE SECOND COLUMN THE FIRST NUMBER IS 68 AND THIRD NUMBER IS 17. 17 DIVIDED BY 68 IS EQUAL TO 4. THIS 4 IS OBTAINED BY DIVIDING THE MIDDLE NUMBER 20 WITH 5. SIMILARLY IN THE THIRD COLUMN THE FIRST NUMBER IS 45 AND THE THIRD NUMBER IS 9. 9 DIVIDED BY 45 IS EQUAL TO 5. SO WHEN WE DIVIDE THE MIDDLE NUMBER WITH 5 AND MULTIPLY IT WITH THE THIRD NUMBER WE GET THE FIRST NUMBER. HERE WE HAVE TO FIND THE MIDDLE NUMBER, SO WE HAVE TO MULTIPLY THE ANSWER WE GOT WHEN WE DIVIDED THE FIRST AND THIRD NUMBERS THAT IS 5 WITH 5,THAT IS 25. SO THE MIDDLE NUMBER IS 25 . IF WE WANT TO CHECK THE ANSWER WE CAN DIVIDE THE MIDDLE NUMBER 25 WITH 5 WHICH GIVES US THE ANSWER 5. WHEN WE MULTIPLY 5 WITH THE THIRD NUMBER 9 WE GET THE ANSWER 45 WHICH IS THE FIRST NUMBER. HENCE OUR ANSWER IS PROVED.SO WE CAN SAY THAT OPTION D IS THE ANSWER.