<span>3 of the 20 toothbrushes are defective, so the initial probability of selecting a defective toothbrush on the first try is 3/20. After that, there will be 2 defective toothbrushes in the remaining 19, so the probability of selecting one of those on the 2nd try will be 2/19. To get the probability of those two events happening sequentially, we multiply the two probabilities. Thus (3/20)*(2/19) = 6/380 = 0.0157, or about 1.6%.</span>
Answer:
The given fraction 
reduces to 
Step-by-step explanation:
Consider the given fraction
We have to reduce the fraction to the lowest terms.
Consider numerator 
We can take x² common from both the term,
Thus, numerator can be written as 
Given expression can be rewritten as ,
We can now cancel 
from both numerator and denominator,
Thus, the given fraction reduces to
A. He eats 1/8 a pound of candy each day.
B. It would take him a total of 8 days to eat a pound of candy.
A. Since he ate 10 ounces in 5 days, you divide 10 by 5 to find he ate 2 ounces per day. Since there are 16 ounces in a pound that would be your denominator (bottom of fraction) and 2 would be the numerator (top of your fraction). You will get 2/16 which if you simplify (divide by 2) you get 1/8.
B. Knowing that there are 16 ounces per pound and he ate 1/8 pound ( 2/16 pound or 2 ounces) a day, you can either look at the simplified denominator to get the answer, or, divide 16 by 2 to get your answer.
I hope this helps!
56 is a decimal part of 70. 56 = 4/5 = .8
Answer:
<em>9*364 - 9*125 - 9*39 = 1,800</em>
Step-by-step explanation:
<em>Mental Calculation</em>
If we detect known patterns in the calculations, we could easily give their results without the use of calculators.
We are given the expression to evaluate:
9*364 - 9*125 - 9*39
The first thing to note is the 9 is a common factor of all terms, thus we take it out:
9*(364 - 125 - 39)
The negative numbers can be easily added
125
+ 39
------------
164
Now our expression is much easier:
9*(364 - 164)
The subtraction of 364-164 is 200, thus the result of the operations is:
9*200. We only need to recall 9*2=18 and add two zeros to get 1,800, thus:
9*364 - 9*125 - 9*39 = 1,800
