Given that op-amp is ideal one so due to virtual short-circuit the voltage at the inverting terminal is zero.
By applying KCL at the inverting terminal we can write
................ (1)Maximum saturation output voltages in both the directions are -10V and +10V
So in order avoid saturation we need to consider 
and 
Take 
Substitute all known the values in the above equation
Checking:
Consider 
Now from equation (1) we can write
Which is less than saturation voltage.
I hope this helps you.....................