Jenny's acceleration was negative during the intervals of time when her speed was decreasing.
That's really all we can tell, because you really haven't given us any information except her name.
Answer:

Explanation:
We know that there is a relation between the speed of light ,frequency and wavelength.This relation can be given as
where v is speed of light
is frequency of light
is wavelength of light
In first case we have given λ=655 nm
so using formula 

Hz
In second case we have wavelength 515 nm so by using above formula


In third case we have wavelength 475 nm
so 

what about it do you need to know love?