A= 13+26+39+...+169What is the sum of the prime numbers that can divide A ?
A)16 B)18 C)20 D)22 E)24
Answers
A= 13+26+39+...+169=
= 13(1+2+3+....+13)=
=13* (13*14)/2=
=13*13*7
=> 13+7=20
So the answer is c)
What number must be added to complete the square? X^2-20x=17
Answers
-117 must be added to complete the square.
There are 6 brown, 5 blue, and 2 orange marbles in a hat. What is the probability of picking two orange marbles in a row without returning the marbles back to the hat? (Write your answer as a fraction.)
Answers
You start out with (6 + 5 + 2) = 13 marbles in the hat. You accidentally knock the hat off the table, they all roll out onto the floor, and you have lost all of your marbles. You pick them up, put them back in the hat, put the hat back on the table, and you still have 13 marbles in the hat.
The probability of pulling an orange marble without looking is
(number of orange ones) / (total number of marbles) = 2/13 .
Now there are only 12 marbles left in the hat. If the first draw was successful, then there's only 1 orange marble left in there. The probability of pulling that one without looking is
(number of orange ones) / (total number of marbles) = 1/12 .
So the probability of BOTH events happening is
( 2/13 ) x ( 1/12 ) = 2/156 = 1/78 .
That's the answer in fraction form, like the question wants it.
That fraction is roughly equal to 1.28 % .
Lets look at the information we have-
6 brown marbles 5 blue marbles 2 orange marbles.
Question:- What is the probability of picking two orange marbles in a row without returning the marbles back to the hat? Solve:-
First add all the marbles:-
6 + 5 + 2 = 13
13 marbles in total.
Now lets write the 1st probability:-
2 orange 13 together
2nd probability:-
13 - 1 = 12
1 orange (left) 12 total (without putting back)
Hope i helped ya!! xD
an employess new salary is 28,140 after getting 5% raise what was salary before increase _and what was last years salary _?
Answers
He got a 5% raise, so 28,140 is 105% of what it used to be.
105% means 1.05
(1.05) x (salary before increase) = 28,140
Divide each side by 1.05 :
Salary before increase = 28,140 / 1.05 = 26,800 .
The rest of the question is nonsense. The salary before increase IS last year's salary.
Consider the quadratic function f (x)= x2-5x+6
Answers
a is the coefficient of x² and is 1 b is the coefficient of x and is -5 c is the term without x and is 6
a=1 b=-5 and c=6 its easy
If a stone with an original velocity of 0 is falling from a ledge and takes 8 seconds to hit the ground, what is the final velocity of the stone? A. 39.2 m/s B. 42.6 m/s C. 78.4 m/s D. 156.8 m/s
Answers
Getting the final velocity of a free fall, we need to use this formula: vf = g * t where g = 9.8 m/s^2 t = time
From the problem given, the final velocity of the stone is vf = g * t vf = 9.8 m/s^2 * 8 s vf = 78.4 m/s