As the sum of marks of others remain unchanged , let their sum be x . As the mean using 83 was 40 , we have ,
(x +83)/100 = 40
x + 83 = 4000
x = 3917
Now mean using 53 ,
(x +53)/100
(3917+53)/100
39.7.
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Answer:
im not sure but i got 30.1
Step-by-step explanation:

Answer:
Ok, first in our series we can see two numbers in the Sigma, one bellow 0, and other above, 4.
This means that the value of k will go from 0 to 4, then all the numbers in the sum are:
(-1/2)^0 + (-1/2)^1 + (-1/2)^2 + (-1/2)^3 + (-1/2)^4
So we have 5 terms in our series.
b) to see the sign in each term, we must solve the powers, remember that:
(-1)^n is -1 if n is odd, and is equal to 1 if n is even, so we have:
(-1/2)^0 + (-1/2)^1 + (-1/2)^2 + (-1/2)^3 + (-1/2)^4
= 1 -1/2 + 1/4 - 1/8 + 1/16.
So the sign in each term of the series alternates.
The common factor is 2 so: 2(4x+3) is the answer
number 7 is as follows Answer: C18.9
Step-by-step explanation:
The perimeter is the length of the outline of a shape. To find the perimeter of a rectangle or square you have to add the lengths of all the four sides. so (5.65x2)+(3.8x2)=18.9 cm