The "relative frequency" is
(number of times a blue marble came out)
divided by
(total number of trials before everybody got bored and quit) .
-- The relative frequency of blue was (20/60) = (33 and 1/3) % .
(Even though 38.5% of the marbles in the jar are blue,
they didn't get picked that often.)
-- The relative frequency of green was (18/60) = 30 % .
(Even though only 26.9% of the marbles in the jar are green,
they got picked more often than that.)
-- The relative frequency of red was (22/60) = (36 and 2/3) % .
(Even though 42.3% of the marbles in the jar are red,
they didn't get picked that often.)
Step-by-step explanation:
Let the two-digit number is 
<u>This can be written as:</u>
- 10x + y, where 1 ≤ x ≤ 9 and 0 ≤ y ≤ 9
<u>The difference between the number and product of its digits is:</u>
<u>Rewrite this as below:</u>
d = 10x - xy + y - 10 + 10 =
x(10 - y) - (10 - y) + 10 =
(x - 1)(10 - y) + 10
<u>We see that:</u>
- 0 ≤ x - 1 ≤ 8 according to the condition given above
- 1 ≤ 10 - y ≤ 10 again according to the condition given above
<u>The value of d is then:</u>
- 0 + 10 ≤ d ≤ 8*10 + 10
- 10 ≤ d ≤ 90
<h3>Proved</h3>
Answer:

The world population at the beginning of 2019 will be of 7.45 billion people.
Step-by-step explanation:
The world population can be modeled by the following equation.

In which Q(t) is the population in t years after 1980, in billions, Q(0) is the initial population and r is the growth rate.
The world population at the beginning of 1980 was 4.5 billion. Assuming that the population continued to grow at the rate of approximately 1.3%/year.
This means that 
So


What will the world population be at the beginning of 2019 ?
2019 - 1980 = 39. So this is Q(39).


The world population at the beginning of 2019 will be of 7.45 billion people.
Answer:
221
Step-by-step explanation:
Day 8 is the first day of the second week.
Day 21 is the last day of week 3.
We need to know the n umber of bicycles made from t = 1 to t = 3
The function is b(t) = 110 + 0.5t^2 - 0.9t, where t is in weeks.
We need to integrate the function with the limits of 1 to 3.





Answer: 221
Answer:
<h2>The specific heat of the metal is 0.274951 calories/gram-degree C.</h2>
Step-by-step explanation:
Let, the specific heat of the container is x calories/gram-degree C.
The container and water gains (18 - 15) = 3 degrees C.
Hence, the transfer of heat is
.
The metal, which is dropped in the water, losses (164 - 18)= 144 degrees C.
Hence, the transfer of heat is
.
As per the given conditions,
.