Question

a body travels 200 CM in the first to second and 220 CM in the next 5 second calculate the velocity at the end of the 7th second from the start

Answer 1

total distance travelled is =420 cm.
and total time taken is =2+5 =7seconds
then
speed =distance/time
speed=420/7=60cm./sec.

Answer 2

$\textbf{Answer is in Attachment !}$