Answer:
It is by definition. 210 means 21 tens or 21 * 10. 30 means 3 tens or 3*10.
Since there is a ten on the top and bottom of the divisor 210/30 is also the same thing as 21/3. All of which is 7 and all of which is true by definition.
Step-by-step explanation:
Answer:
6 hours
Step-by-step explanation:
if it costs 12 dollars to rent it at first then that subtracts 12 dollars from the total 30.
this leaves you with 18 buck, divide 18 by 3 and you get 6, she had it for 6hours