The answer is B:40 hours. You take 200 divided by 20 to get 10 (the amount of 20 page sections he needs to read) and then multiply 10 by 4 (the speed he reads).
All you would do is multiply .9 by 20
.9*20=18
90% of 20 is 18
72.5%
You can get this by dividing the new price by the original price and then multiplying by 100.
If a^ x = b then:
x = log_{a}b
For:
4^{7} = 16384 \\ log _{4}16384 = 7
Answer:
I think Substitution
Step-by-step explanation:
Because x is already solved for in the second equation.
