Answer:
they work together, it will take 2.4 hours to build the wall.
Step-by-step explanation:
One bricklayer can build a wall in 6 hours.
One hour work = 
Another bricklayer can build the same wall in 4 hours.
One hour work = 
They can together, how long will take them to build the wall.
Let's take "t" the time taken to build the wall.
The sum of their work rate = 1 (To build the wall)
Now we have to solve this equation. Take LCD of 6 and 4.
The LCD (least common divisor) of 6 and 4 is 12.
5t = 12*1
5t = 12
Dividing both sides by 5, we get
t = 
t = 2.4 hours.
So, they work together, it will take 2.4 hours to build the wall.
Answer:
x = 3
Step-by-step explanation:
3(10-x)=21
30-3x=21
-30 -30
-3x=-9
x=3
Answer:
letter C: 100
Step-by-step explanation:
This problem can be configured as an arithmetic progression:
The first value is 10, the ratio is also 10 (the multiples of ten are 20, 30, 40, ...) and the number of terms is 19 (10, 20, 30, ... , 180, 190 -> total of 19 numbers).
So, we can use the following formula to calculate the sum of all these numbers:
Sn = n(a1 + an)
/2
where Sn is the sum, n is the number of terms, a1 is the first term and an is the last one.
The result we want is the average of the sum, so we need to divide Sn by n:
Average = Sn/n = n(a1 + an)
/2n = (a1 + an)
/2 = (10+190)/2 = 200/2 = 100
The correct option is letter C.
Answer:
Step-by-step explanation:
For a multiple regression model with 3 independent variables,
Y = A0 + A1X1 + A2X2 + A3X3
The hypotheses for the global test of a multiple regression model are:
Null hypothesis H0: there is no relationship between the slopes - A1, A2, A3 - and the outcome. A1, A2, A3 = 0; R^2 = 0
Alternative hypothesis H1: there is a relationship between at least one of the slopes and the outcome. One of A1, A2, A3 is not equal to zero. R^2 is not equal to zero.
Answer:
6
Step-by-step explanation:
its 6 because half way between 5 and 7 is 6
