Answer:
The correct options are 1, 3 and 4.
Step-by-step explanation:
We need to find the expressions whose simplified form is a rational number.
Rational number: If a number is defined in the form of p/q where p and q are integers and q≠0, then it is called a rational number.
For example: 0,2, 4.3 etc.
Irrational number: If a number can not defined in the form of p/q, where p and q are integers and q≠0, then it is called an irrational number.
First expression is

12 is a rational number.
Second expression is

is an irrational number.
Third expression is

21 is a rational number.
Fourth expression is

5 is a rational number.
Therefore, the correct options are 1, 3 and 4.
Answer: 12pm
Step-by-step explanation: it takes him 2 hours to fill 1800 another 2 hours would be 12pm if you have 1000+1000 you get 2000. then add 800 and 800. you get 1600 add them all together you get 3600.
Answer:
y = 60
Step-by-step explanation:
From the information we get:
x quantity of 4 dollars coffee used in the mix
y quantity of 7 dollars coffee used in the mix
For the quantity of coffee to be sold a 7 $/pound ( 90 pounds)
Then 6*90 = 540 $
Therefore
x + y = 90 and
4*x + 7*y = 540
A two equations system we solve for x and y
y = 90 - x
4*x + 7* ( 90 - x ) = 540
4*x + 630 - 7*x = 540
- 3*x = - 90
x = 30 pounds and
y = 90 - 30
y = 60
We should use 60 pounds of the seven $ coffee
Answer:
1,280
Step-by-step explanation: