Question

A body moving along a straight line at 40m/s undergoes an acceleration of 4m/s . After seconds its speed will be

Answer 1

increase due to apply more force on acceleration

Answer 2

I guess your question is a bit wrong..
But anyways if it suffers an acceleration of 4m/s than its velocity increases by 4m/s every second..
similarly after 1 second it will be 44m/s
After 5 sec 60 m/s ,after 10 sec 80m/s and so on...

Hope this helps..