Question 331127
let the bigger number be a
smaller number be b
a-b=10.................1
..
2a=b+20
2a-b=20................2
multiply equation 1 by -1 and add equation 2 to it
-1(a-b)+(2a-b)=-10+20
-a+b+2a-b=10
a=10
plug value of a in equation1
10-b=10
b=0