5% total increase, as 3 to 60 is 1/20 (5%)
The answer is 3
Multiply 6 by 3 to get the total amount of money for the books then minus the answer 18 which you get from 6 x 3 = 18
Then minus 18 from 21 to get $3
21 - 18 = 3
Step-by-step explanation:
A....
Solution ,





Change the sign of both side


B....
Solution,

Multiply the both side by the least common multiple to eliminate the fraction...



