Answer:
390
Step-by-step explanation:
The formula of sum of arithmetic sequence is
The number of this series are 2, 4, 6, 8, 10, 12, . . . . , 60.
The first term ( a ) = 2
The 30th even number is 60
The Tn is the term of the sequence
So the equation is
30/2 x ( 2 + )
= 60
30/2 x ( 2 + 60 )
30/2 x (62)
1860/2
390
Given :
An alloy is a mixture of metals. Suppose that a certain alloy is made by mixing 50 g of an alloy containing 12% copper with 78 g of an alloy containing 92% copper.
To Find :
How many grams of copper are in the resulting mixture what percentage of the resulting mixture is copper.
Solution :
Mass of copper in 50 gm alloy = .
Mass of copper in 78 gm alloy = .
Total mass of copper, ( 6 + 76.44 ) gm = 82.44 gram.
Percentage of copper in resulting mixture :
Hence, this is the required solution.
Answer:
Hence, the ratios are given by 5:7, 25:49, 125:343.
Step-by-step explanation:
We are given two spheres such that:
Volume of small sphere = 250
Volume of large sphere = 686
.
Then the ratio of volume = 250 : 686 = 125 : 343.
Since, the volume of a sphere = , this gives us that the ratio of the radius = ∛
: ∛
i.e. The ratio of the radius = ∛125 : ∛343 = 5 : 7.
Further, as the surface area of a sphere = , this gives us that the ratioof surface area =
:
i.e The ratio of the surface area = :
= 25 : 49
So, the ratio of the surface areas = 25 : 49.
Hence, the ratios are given by 5:7, 25:49, 125:343.