The common difference of the A.P. \(b_1, b_2, \ldots ., b_m\) is 2 more than the common difference of A.P. \(a_1, a_2, \…

The common difference of the A.P. \(b_1, b_2, \ldots ., b_m\) is 2 more than the common difference of A.P. \(a_1, a_2, \ldots ., a_n\). If \(a_{40}=-159, a_{100}=-399\) and \(b_{100}=a_{70}\), then \(b_1\) is equal to:

[JEE Main 2020, 6 Sep (Shift 2)]