250 – (1/2 x 150 ) = 350 : n

250-(1/2×150)=350:n
250-75=350:n
175=350:n
n=350:175
n=2

250 – (1/2 x 150 ) = 350 : n250 – 75 = 350 : n
175 = 350 : n
n = 2