If a > 0 and b < 0, then which of the following must be true.
ab > 0
a + b < 0
a - b > 0
a + b > 0
b - a > 0

We need to find the correct answer on the given choices:

If a > 0 and b < 0, then The answer is a + b > 0
let’s give a specific example:
let’s have a = 1
and b = .20

Now, let’s try calculating if our answer is correct.
Thus a + b > 0
=> a + b
=> 1 + .20
=> 1.20
and 1.20 is greater than 0.
=>Therefore 1.20 > 0 = a + b > 0

What’s the question?