Acity's sales tax is 0.07. write this decimal as a fraction and tell how many cents of tax are on each dollar.

To transform decimal to fraction its easy to read decimal. So
0.07 is seven hundredths. Now we know that in the nominator should be seven and in the denominator 100.
So
. - the result
 
Now we have to multiply 0.07 by dollar.
0.07*1$=0.07$ = 7 cents - the result