Answer:
Explanation:
1. cools quickly on the earth's surface
Extrusive igneous rock
2. cools slowly beneath the earth's surface
Intrusive igneous rock
3. formed from the remains of living organisms
Organic sedimentary rocks
4. formed from pieces of other rocks cemented together
Clastic sedimentary rock
5. formed when dissolved minerals harden
Chemical sedimentary rock
6. formed from heat and pressure
Metamorphic rocks
Explanation:
For an experimental result to be considered acceptable, all relevant variables involved in the experiment must be taken into account, by isolating it, performing it under controlled conditions and modifying the conditions under which it takes place. This, with the objective of excluding alternative explanations in the analisis of the experimental data. Therefore, if these steps are followed appropriately, experimental data are trustworthy. The reliability of the experiment increases when it is replicated by other researchers and the same results are obtained.
Answer:
Time taken by A and B is 1.2 hr.
Explanation:
Given that
Time taken by tank when all(A+B+C) are open = 1 hr
Time taken by tank when A+C are open = 1.5 hr
Time taken by tank when B+C are open = 2 hr
If we treat as filling of tank is a work then
Work = time x rate
Lets take work is 1 unit
1 = 1(1/a+1/b+1/c) ---------1
1 = 1.5(1/a+1/c) ----------2
1 = 2(1/b+1/c) --------3
From equation 1 and 3
1=1(1/a+1/2)
a=2
Form equation 2
1 = 1.5(1/2+1/c)
c=6
From equation 3
1 = 2(1/b+1/6)
b=3
So time taken by
A is alone to fill tank is 2 hr
B is alone to fill tank is 3 hr
C is alone to fill tank is 6 hr
So 
Time taken by A and B is 1.2 hr.
Answer: (1, 30), (2,10), (3,40), (4,20)
Explanation:
