I believe its the last choice
Step-by-step explanation:
(b) If 
then
Note that 
cancel out so we get
Solving for 
we get
(c) I'm not sure what the problem is asking for but here goes. As r doubles, 
becomes
In multiplying fractions, you multiply the numerators and denominators.
51 / 2 * 21 / 3
can be reduced as
(17 / 2) * (21 / 1)
357 / 2 --> This is the answer based on the given.
Assume that its a mixed fraction:
5 1/2 * 2 1/3
11/2 * 7/3
= 77 /6
Answer: let the no of paperback books be x and hardcover books be y
4y - x = 3
Therefore, x - 4y = -3 -----(1)
x + y = 447 ----(2)
Put x = 447 - y in eqn 1
447- y - 4y = -3
-5y = -3 - 447
-5y = -450
y = 90
x = 357
Step-by-step explanation:
