x = 1st number
y = 2nd number
x + y = 200
x : y = 4 : 6
ok! let's substitute numbers!
4 * 10 : 6 * 10
40 : 60
40 + 60 = 200
100 ≠ 200
Too small!
That is exactly two times smaller than 200 so let's try 2 times greater than multiplying by 10
4 * 20 : 6 * 20
80 : 120
80 + 120 = 200
200 = 200
Now it says to find the larger number. Which is y.
x :y = 4 : 6 = 80 : 120
so, y is 120
y = 120
Answer : y = 120. The larger number is 120.