find the base of the number?
24+17=40

i did as 2*b+4+b+7=4*b

then i got answer as 11

if i add that i.e 40=41
4*b=4*b +1

then i am not getting answer why?

 

The first half of your post is correct.

But what the heck do you mean by "if I add that i.e 40=41"?

 

i am just adding 24 and 17 and then i am proceeding.Why it is wrong way of doing

 

24(base 11) = 26 (base 10)
17 (base 11) = 18 (base 10)
40 (base 11) = 44 (base 10)

So, using just base 10 on the left you have 26 + 18, which equals 44
On the right, you have 44

The equality is correct and the base is 11.

John

 

You have to add 24 in base 11 to 17 in base 11. This operation is shown in your original problem statement. Since we are familiar with base 10 arithmetic, let's look at the addition in base 10.

24 base 11 = 2*11+4 = 26 base 10
17 base 11 = 1*bb+7 = nn base 10

(I've left some of the values for you to complete)

So add 26 to nn. Then convert 40 base 11 to decimal and compare your results.