Considering acceleration is constant, we can write
v=u+at
As increase in velocity in 1s is given as 50ms−1, therefore
⇒a=50ms−2
Now, displacement covered between given time interval is,
125=ut+21at2
⇒125=u+2a
⇒u=100ms−1
Velocity after 1s will be, v=100+50=150ms−1
Therefore, displacement covered in (t+1)sto(t+2)s will
∴Snth=vt′+21a(t′)2,wheret′=1s
=175m