Dau coroana sormea e a 4-a si eu nu stiu nimic

a)760,645,530,415,300.
b)190,280,370,460,550.
c)1,5,25,125,625.
d)81,27,9,3,1.
e)269,368,467,566,665.
f)950,851,752,653,554