A few days ago

# Math question?!?

ok, here’s the problem:

The 14 digits of a credit card number are written in the bowes below. If the sum of any three consecutive digits is 20, find the value of A.

theres a pic below the problem that has numbers and boxes, so when there is a *, that means a blank box.

A*7********7*4

tell me the answer and explain step by step(clearly plz) how u got that answer

A few days ago
theon castillo

Ok i was able to figure out the value of A by looking at a pattern

now

you have the numbers listed as A*7********7*4=now lets change that up and give some of these * a symbol.

such that it becomes AX7q******G7P4

now it’s consecutive number (1,2,3 etc ) whose sum give a value of 20 so we can form the following equations

A+X+7=20 (1)

7+p+4=20 (2)

x+7+q=20 (3)

g+7+p=20 (4)

——————————————–

from equation (4) we get

———————————————

g+7+p=20 (4)

7=20-(g+p)

———————————————————

substituting 7=20-(g+p) into (2) we get

20-(g+p)+p+4=20

-g = – 4

g=4

———————————————————-

substituting this value (g=4) into equation 4

4+7+p=20

p=9

———————————————————–

now I don’t know if I should make this assumption but it seems that the numbers loop so

I’m expecting the value of A to be 9.

as A*7********7*4

=AX7q******G7P4

=AX7q*******4794

SO FROM LOOKING AT THIS THE VALUE OF A IS 9

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A few days ago
Jackie
How many spaces are between the first 7 and the last 7? If there are 8 (which is how many *’s I counted), A = 9. You can figure this out by starting on the right hand side. If three consecutive digits must equal 20, the number between the 7 and the 4 must be 9, since 20-7-4=9. Once you have this number, you can figure the number to the left of the 7 since 20-7-9=4. Now you can see that it is repeating. A*794794794794

So then the star must be 4, and that makes A = 9.

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