The given ratios 3: 5 and 15: 25 are equal. Because when you divide the ratio 15: 25 by 5 on both numerator and denominator, the first ratio 3: 5 can be obtained. Similarly, when you multiply the first ratio 3: 5 by 5, the ratio 15: 25 can be obtained.
Answer:
0
Step-by-step explanation:
Thinking process:

=
by Stoke's Theorem
=
since z = 
55% of 120 is just 66
add that with 120, 186
so... 186 books