Hello,
67.935=67+935/1000=67+187/200 = 67|187/200
======================================
In plain and short, nope, their bases must be the same in order for the exponents to be summed up, whilst keeping the same base.
Amount saved:50I60I70l80l AND ON......
......weeks......:0..I1...l2..l3..l ..........AND ON
amount saved =x
weeks=y
after every y+10=x