Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?

conduct a laboratory test for the metal

design a prototype aircraft to tested

review any necessary adjustment

launch the new material as an alternative aircraft material;

Explanation:

A. before any decision is taken, or any conclusion is made, a destructive and non destructive test should be conducted on the metal.

this test includes:

1. bearing capacity test,

2. shear test

3. Ductility test

4. hardness test

5. Torsion test

6. heat resistance test

7. accuracy and durability test

8. corrosion resistance test... e.t.c

After this test is conducted, necessary stability and safety calculation will be done to know the best material that is safe and cost effective.

B. design a prototype aircraft to tested: A prototype aircraft is constructed using the normal process of aircraft construction and its is being test run.  

C. review any necessary adjustment: Any review noticed will be work on.

D. launch the new material as an alternative aircraft material;

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form