In performance always assume an engine failure unless the question states otherwise. So we only have 100,000N of thrust. If the aircraft is flown correctly the drag will stay almost the same.
The question gives you the formula for the gradient, expressed as a percentage, as SIN theta = T-D/W
Change the formula around to : W = T-D/SIN theta
Substitute the known values W = 100000N- 72569N/ 0.027 ( this is SIN theta 2.7% expressed as a decimal.)

This gives 1015962Newtons. Now divide this by the gravitational constant 10m/sec2
Answer 101596 kgs.