# The Mathematical Challenge

Dear Friends,

Can you find out the number in “?”,

If you can solve it in less than 3 mins then you are a Genius 🙂

Nice to know that so many of our Readers are geniuses -:)
The Correct answer in 91 .

### 399 Responses to The Mathematical Challenge

1. naeem February 17, 2015 at 12:36 PM #

91

less then a minute

• eissa April 3, 2015 at 10:58 AM #

A.(2+3)*5=15,b.((3+4)*4=28,c.(4+5)*5=45,d.(5+6)*6=66,e.(7+6)*7=91

2. Sabuppa February 15, 2015 at 10:25 PM #

12×2=24+4 =28
20×2=40+5=45
30×2=60+6=66
42×2=84+7=91 (answer)

3. Pareethu Bava Khan November 8, 2014 at 4:33 PM #

91

4. ALI AHMED August 19, 2014 at 7:57 PM #

91. The relation in second column third column.
Just add 1,2 3,4 and 5 in third column figure and multiply with second column figure

5. WAZ August 19, 2014 at 6:08 PM #

91

6. Tahir August 14, 2014 at 4:38 PM #

It is (8 x 7 = 56) + (7 x 5 = 35) = 91

7. A W Quazi February 13, 2014 at 4:07 PM #

It’s 91

All the numbers go up by additional 4 to the difference. 13; 17; 21. So the next will be 25 which is added to 66 giving a result of 91.

8. FAISAL RIZWAN November 26, 2013 at 4:55 PM #

See the 4th column
15+13=28
28+17=45(13 is increased by 4)
45+21=66(21 is increased by 4)
66+25=91(25 is increased by 4)

so correct answer is 91

• FAISAL RIZWAN November 26, 2013 at 5:00 PM #

good

9. sunny August 17, 2013 at 11:30 AM #

91 i.e 15+13=28, 28+17=45, 45+21=66, & 66+25=91 just add 4 to every next step so simple dont confuse with table

10. ESSAM July 29, 2013 at 7:21 PM #

(13*56)/8=91

11. ALI AHMED June 18, 2013 at 5:07 PM #

91

12. mohammed aslam askeri May 4, 2013 at 9:27 PM #

91

13. Mani March 18, 2013 at 4:50 PM #

91

14. wahab adegoke January 11, 2013 at 7:36 PM #

great I got the answer to be 91 within one minute

15. Bassem January 4, 2013 at 11:43 AM #

91 ^_^

16. Mahdi December 28, 2012 at 7:45 AM #

The answer is: 91 . There are many methods to solve it . If you take the fourth colomn you will find the differances between (15 & 28) -( 28& 45) -(45&66) are 13 & 17 & 21 , so the last differance will be 25. If you add 25 to 66 the total must be 91 .I think that it’s a sequence .I took less than one minute.

17. Chand November 19, 2012 at 11:14 AM #

91 within less than thirty seconds.

18. ibrahim November 6, 2012 at 1:25 PM #

it is 91, but by:
12 x 2 – (9) = 15
20 x 2 – (12) = 28 and so on.

19. azra haider October 30, 2012 at 3:10 PM #

the answer is 77 but what is the correct answer?

• Hayatudeen Adamu June 29, 2013 at 4:26 PM #

91 is the correct answer

20. azra haider October 30, 2012 at 3:05 PM #

The answer is 77

21. moammad azeem October 28, 2012 at 7:31 PM #

91 is the answer

22. [email protected] October 18, 2012 at 1:01 PM #

91 in 30 sec

23. Sonah October 10, 2012 at 1:11 PM #

It’s 91. As explained by Mr.Shaukat. Got it after a seond attempt, unfortunately.

24. shaukat October 7, 2012 at 9:55 AM #

3×5=15
4×7=28
5×9=45
6×11=66
7×13=91

25. Pritpal Singh Jhutti September 13, 2012 at 7:12 PM #

91

26. hosam September 5, 2012 at 1:58 AM #

91

27. khalid umer August 27, 2012 at 11:10 PM #

Answer is 91

28. ashraf August 18, 2012 at 8:41 AM #

Answer is 91

29. khalid August 17, 2012 at 1:21 PM #

equation
x4=(x1+x2)*x2
x5=x2*x3

30. Musa August 10, 2012 at 5:57 PM #

1st Row: 2+3=5X3=15
2nd Row:3+4=7X4=28
3rd Row:4+5=9×5=45
4th Row:5+6=11X6=66
5th Row:6+7+13X7=91 (Answer)

31. kamran July 13, 2012 at 5:54 PM #

91

32. Mohioudin July 11, 2012 at 5:00 PM #

91

33. Hemaid M. Hemaid July 1, 2012 at 7:09 PM #

91

34. Nizam HM June 29, 2012 at 6:02 AM #

There are many ways to get the results. almost all methods have been used by viewers. Congratulations. Its also an old quiz.

• sabrim July 8, 2012 at 11:10 PM #

the answer is 91
why?
in the mentioned row we added 13 to the secound number ‘ 17 to the third’
21 to the fourth and so we have to add21 to the number 66 so the number are must be 91