Math
posted by Kris .
A number has four digits. the sum of the first and last digits is twice the second digit. The second digit is 2 less than the third digit. The last digit is twice the first. Some of the digits are alike. what is the number??

This is a hard one. What helps me is to read each part of the problem carefully. Write the numbers you think on a piece of paper. When you find out if it is wrong put an x next to it. This will narrow down the process.

i got the equations from my sister
a+d= 2b
b= c2
d=2a
but what do i do next?