Answer:
B. 13
Explanation:
We have two unknown numbers, let's have two variables for these two unknown numbers, X and Y.
"The sum of two numbers is 46 and their difference is 20."
Meaning we have two equations :
X + Y = 46
X - Y = 20
Looking at the last part of "their difference is 20." We can assume X = Y + 20
So substitute the assumed equation into X + Y = 46
(Y + 20) + Y = 46
2y + 20 = 46
Subtract 20 from both sides :
2y = 26
Divide 2 by both sides :
y = 13
There you go.