Answer:
Metals which react with steam form the solid metal oxide and hydrogen gas.
In general, the more reactive the metal, the more rapid the reaction. Aluminium is unusual, because it is a reactive metal that does not react with water. Its surface forms a protective layer of aluminium oxide that keeps water away from the metal below.
The apparatus used to react a metal with steam and collect the gas produced is shown below.
Let's call the width: w
the lenght is then 3w+4 ("4 more than 3 times the width")
and the parameter would be 2(w+3w+4), that is 2*(4w+4), that is 8w+8.
this is also equal to 18.4:
8w+8=18.4
8w=10.4
w=1.3
this is the width, and the lenght is:
4+3*1,3=4+3.9=7.9
and the area is their product:
1.3*7.9=10.27
Work it exactly like the other one with Wilda and Karla.
Juan takes 15 hours to do a job ... he does 1/15 of it in an hour.
His father can do it in 6 hours ... he does 1/6 of it in an hour.
Juan works alone for 4.5 hours. In that time, he does 4.5/15 = 0.3
of the job. When his father joins him, there's only 0.7 of it to finish.
Working together, they do (1/15 + 1/6) = (2/30 + 5/30) = 7/30 of the job
each hour.
How many times do they have to do 7/30 of the job in order to finish
the 7/10 of it that remains ? That will be the number of hours they need.
(7/10) / (7/30) = 7/10 x 30/7 = <em>3 hours</em>.
Then they can knock off while it's still daylight, and go for a swim.
Answer:
- large: 18.5 kg
- small: 15.75 kg
Step-by-step explanation:
Let b and s represent the weights of the big and small boxes, respectively. Then the two delivered weights can be summarized as ...
5b +6s = 187
3b +2s = 87
We can eliminate the "s" variable by subtracting the first equation from 3 times the second:
3(3b +2s) -(5b +6s) = 3(87) -(187)
4b = 74 . . . . . collect terms
b = 18.5 . . . . . divide by 4
Using this value in the second equation, we find ...
3(18.5) +2s = 87
2s = 31.5 . . . . . . . . subtract 55.5
s = 15.75 . . . . . . . . divide by 2
The large box weighs 18.5 kg; the small box weighs 15.75 kg.
Answer: That’s weird I don’t see an option for the answer I got, I’m positive it’s correct though. It’s 24/25 or 0.96 in decimal form
Step-by-step explanation:
