The normal annual precipitation at stations X, A, B, and C are 700 mm, 1000 mm, 900 mm and 800 mm respectively. If the storm precipitation at three station A, B and C were 100 mm, 90 mm and 80 mm respectively, then the storm precipitation for station X will be
1
70 mm
2
80 mm
3
90 mm
4
105 mm