The respective storm totals at three surrounding stations A, B and C are 110, 90 and 70 mm. If the
normal annual precipitation amounts at stations X, A, B and C are respectively 1000, 1100, 1200
and 1250 mm, the estimated storm precipitation at X is
(A) 75 mm
(B) 77 mm
(C) 79 mm
normal annual precipitation amounts at stations X, A, B and C are respectively 1000, 1100, 1200
and 1250 mm, the estimated storm precipitation at X is
(A) 75 mm
(B) 77 mm
(C) 79 mm