please help work these

Propose a molecular formula for a compound that exhibits the given peaks in its mass spectrum: (M)+ at m/z=72, relative height = 38.3% of base peak (M+1)+ at m/z=73, relative height =1.7% of base peak. Complete the molecular formula CaHbNcOd by entering the numeric subscripts below (enter " O for ony element that is not in the molecular formula). \# of C atoms (a): \# of Hatoms (b): H of N atoms (c): A of O atoms (d): Propose a molecular formula for a compound that exhibits the given peaks in its mass spectrum: (M)+ at m/z=68, relative height = 100% (base peak) (M+1)+ at m/2=69, relative height =4.3%. Complete the molecular formula CaHbNcOd by entering the numeric subscripts below (enter " 0 for any element that is not in the molecular formula). 4 of C atoms (a): \# of Hatoms (b): A of Natoms (c): N of O atoms (d)