I Need help in Maths, PLEASE!!!

[ugochukwu]

a) Bronze is an alloy of copper and tin in the ratio 7:3. How much tin must be added to 35kg of copper to make batch of bronze?

 

and is this right ...

 

7:3

7 + 3 = 10

Copper = 35 kg

Tin = 10.5 (Tin)

35kg ÷ 7 = 10 x 5 = 50 so therefore

 

50/10 x 3 = 15kg (tin). so 15kg of tin will be required to make a batch of bronze.

 

 

I have a diagram that shows a cylindrical tank designed to store oil. it has a height of 3.4m and a lenght of 2.8m. could you tell me how i am to solve this problem.

 

if

 

The outside of the tank is to be painted. It is stated that the paint in one tin will cover an area of 5m2. How many tins of paints are needed to do the job?

 

so please, can some one tell me the formular for this. I don't think it is pi r2 H or is it 2 pi r x (sum of radius and height). can someone please solve this for me, i will give you a donut. just help me, please.

[JaKiri]

You're right for the first one.

 

As for the second...

 

:pi:r²h is the equation for the volume (you can tell because there's 3 lengths being multiplied).

 

The 2nd equation you gave is correct for the surface area.

[jpat1023]

for a) you could have just set up a proportion...it seems like that would have been easier.

[ugochukwu]

A proportion? hmm, i wish i had the picture to show you. the problem was that i couldn't find the radius. Anyways, i will see what i can do with the formular you have given me. Thanks to you all.

 

One more thing, can you guys solve it for me, do the calculations i mean. so i can use your answer to make corrections. sorry for the inconvinience