Answer:
The probability that no more than more than 11 of them need correction for their eyesight is 0.00512
No, 11 is not a significantly low low number of adults requiring eyesight correction .
Step-by-step explanation:
A survey showed that 77% of adults need correction for their eyesight.
If 22 adults are randomly selected, find the probability that no more than more than 11 of them need correction for their eyesight.
n =22
p = 0.77
q = 1-p = 1- 0.77=0.23
We are supposed to find 
Formula : 
Using calculator
So, The probability that no more than more than 11 of them need correction for their eyesight is 0.00512
No, 11 is not a significantly low low number of adults requiring eyesight correction .
X liters of 10% + (30 - x) liters of 22% = 30 liters of 15%
<span>Plugging in the numbers </span>
<span>x(10) + (30 - x)22 = 30(15) </span>
<span>Distribute </span>
<span>10x + 660 - 22x = 450 </span>
<span>Combine like terms </span>
<span>-12x = -210 </span>
<span>Divide both sides by -12 </span>
<span>x = 17.5 </span>
<span>30 - x = 12.5 </span>
<span>17.5 liters of 10% + 12.5 liters of 22% = 30 liters of 15%
THE TRICK IS TO JUST USE ONLY ONE VARIABLE</span>
Answer:
3 years
Step-by-step explanation:
As with many age problems, you can reason it without equations. If Tom is 13 now, 2 years ago he was 11. If the total age of the two cats at that time was 15, then Tim was 15 -11 = 4.
That means Tim is now 4+2 = 6, so will be 9 in 3 years.
_____
<em>Additional comment</em>
If you want to write equations, there are several ways you can do it. We often like to use variables to represent the current age. We can assign ...
x = Tim's current age; y = Tom's current age.
The sum of their ages 2 years ago was ...
(x -2) +(y -2) = 15
Tom's current age is 13, so we have y=13. Using that in the equation gives ...
x -2 +13 -2 = 15
x = 6 . . . . . . . . . . subtract 9, collect terms
That's Tim's current age, so Tim will be 9 years old in 3 years.
