A real problem which make me mad

Final 1084 views 11 replies

Renjith S Nair

Accountant

94 Points Joined March 2008

hay friends,

I lost my sleep due to this question.Pls some one help.very urgent

4+5 = 9

5+4 = 21

6+9= ?

Replies (11)

PSPSPS

Practicing

1344 Points Joined September 2012

Based on 4 + 5 = 9

5 + 4= 21

6 + 9 = 15

9 + 6 = 75

vidhyalaksshmi

student

190 Points Joined February 2008

how did u get the answer ? can anyone explain, according to me it should me 15 and 45.

Jithin

Learner

1057 Points Joined May 2010

Hi Renjith, here is my solution. Hope its correct & u sleep well 2day

Step 1:Select the highest integer in LHS..lets assume it as n(for convenience sake). Split it as 1+(n-1). For example, in the eq. 4+5=9, 5 is the highest integer in LHS. 5 will be written as 1+(5-1) or 1+4. So the eq. is rewritten as 4+1+4=9. Similarly eq. 5+4=21 is rewritten as 1+4+4=21.

2)Step 2:Multiply the 2nd number in the LHS of eq. with the 3rd number. In eq. 4+1+4=9, multiply 1(2nd no) with 4(3rd no). Add the resultant product,i.e.4, to 1st number & 2nd number. Thus we get 4+4+1 which is the same as RHS,i.e.9. Similarly in eq.1+4+4=21, we multiply 4 with 4. The resultant product is 16 to which we add 1 & 4. The sum=16+1+4=21=RHS.

Step 3:Now lets apply the above steps to find 6+9. We write 6+9 as 6+1+8. Multiply 1 with 8. 8 the resultant product is added to 6 & 1. 8+6+1=15. So 6+9=15. Now letz check the reverse sum, 9+6. 9+6 is written as 1+8+6. Multiply 8 with 6. The resultant product 48 is added to 1st number & 2nd number. 48+1+8=57. Therefore 9+6=57.

RENU SINGH

✩ §m!ℓ!ñġ €ม€§ fℓม!ñġ ђ♪gђ✩

21627 Points Joined March 2011

Typically tough q for me ...

koi easy tarika ho to muje bi bata dena

nikhil jain

CA-Final-Student

58 Points Joined June 2011

Check this out....

4+5=9

5+4=21 [its 5+(4*4)] this is the actual logic..

Similarly,

6+9=15 &

9+6=45 [9+(6*6)]

CA Deepak Rathore

223 Points Joined August 2011

Originally posted by : nikhil jain
	Check this out.... 4+5=9 5+4=21 [its 5+(44)] this is the actual logic.. Similarly, 6+9=15 & 9+6=45 [9+(66)]

Jithin

Learner

1057 Points Joined May 2010

Originally posted by : nikhil jain
	Check this out.... 4+5=9 5+4=21 [its 5+(44)] this is the actual logic.. Similarly, 6+9=15 & 9+6=45 [9+(66)]

Hi Nikhil, there is a problem with ur logic. It cant be applied to 4+5=9. If u do, u will get 29 & not 9. Whatever logic u apply, u have to apply it to both the cases,i.e.both 4+5=9 as well as 5+4=21. I can also say (5*5)-4=21 and use the same method to get 9+6=75[(9*9)-6]. But thats not the correct way..