It is supposed that we have a decimal system because we have 10 fingers. An alien sees the sum 15+5 and answers correctly 22.
How many fingers does the alien have?
A-10
B-6
C-22
D-8
E-15
P.S. Could you give the answer + the demonstration.
P.S.S. Sorry i'm new here so i don't know if i can ask this here or if there are threads for this questions.
>>8001388
it's 12
>>8001388
I got 8.
>>8001412
tuck your thumbs in and count, everytime you get to your last finger, count it as a multiple of ten.
so
1-2-3-4 5-6-7-10
11-12-13-14 15-16-17-20
21-22
>>8001388
1x+5+5 = 2x+2
x = 8
12
10 units + 1 full base-whatever unit = 2 full units + 2 units
if base=8, 10 units is 1 full base plus two extra
>>8001421
10 in base ten = 15 in base x
2 * 410 + 3x = 281 - 5x
Solve for x.
>>8001423
woop, ignore the 12. answer is 8.
>>8001418
This, answer is 8
>>8001388
This looks like a horribly worded question.
>>8001824
It is actually the 1st question of a university entry test.
>>8001388
D-8
Using the notation 8 = 0d8 = 0o10 (in other words 0d for base-10, 0o for base-8)
0o15 + 0o5
=0d13 + 0d5
=0d18
=0o22
>>8001388
Also there's a joke about this. Why do mathematicians get Christmas and Halloween confused?
Because DEC25 = OCT31 (0d25 = 0o31)
>>8001388
The alien has 10 fingers from its own perspective.
