Answer:
The correct answer is B) 18%
Step-by-step explanation:
Note that the vaccine is already and is 80% effective. This means that if the entire population was administered with the vaccine, only 8/10 would gain immunity leaving 2/10 or 0.2 exposed.
If the new vaccine, therefore, is supposed to be 90% effective, it is only pragmatic to administer it against those who do not have immunity which is 0.2 of the existing population.
So to get the percentage that will develop immunity, we have:
0.2 x 0.9 = 0.18 or 18%
Cheers!
Given:
A number 72.
To Find:
12% of 72.
Solution:
The given problem can be solved using the concepts of percentages and their applications.
1. The given number is 72.
2. x% of a number n is given by the formula,
=> x% of n = ,
3. x% of a number can also be defined as x parts of 100 multiplied by the given number.
4. 12% of 72 can be calculated using the above number,
=> 12% of 72 =
=> 0.12 x 72,
=> 864/100,
=> 8.64.
Therefore, 12% of 72 is 8.64
X=9 Combine like terms, Move constant, then calculate.
Answer:
option D
Step-by-step explanation:
take 39 degree as reference angle
using cos rule
cos 39 = adjacent / hypotenuse
0.77 = x / 7
x = 7*0.77
x = 5.39
x = 5.4
The first thing we must do for this case is to define variables.
We have then:
x = Tim's age
Now we write the equation:
x + 7 = 3 (x-19)
Answer:
Tim's age in 7 years will be three times what it was 19 years ago:
x + 7 = 3 (x-19)
