Answer:
(n-1) / 2
Step-by-step explanation:
We have that the sum has the form of:
Sn = n / 2 [2 * a + (n-1) * d]
we compute the terms of a and d
a = 1 - 1 / n
a = (n - 1) / n
, that is, the first term, in the case d is the subtraction between the second and the first term, thus:
d = 1 - 2 / n - (1 - 1 / n)
d = 1 - 2 / n - 1 + 1 / n
d = - 1 / n
now if replacing these values:
Sn = n / 2 * [2 * (n - 1) / n + (n-1) * (- 1 / n)
Sn = n / 2 * [2 * (n-1) - (n-1)] / n
Sn = 1/2 * (n-1)
Therefore, the value of that sum is (n-1) / 2
Answer:
1 bowl = 1/3 cups
6 bowls = (1/3) * 6
= 2 cups
So, the container hold 2 cups of sugar
Step-by-step explanation:
Answer:
3 student.
Step-by-step explanation:
From the first statement:
Let the total score be T
Let the total number of student be x
The average of the score = 72
Average = Tota score / number of student
72 = T/x
Cross multiply
T = 72x ..... (1)
Second statement:
One more student took the test and the average becomes 76 with the student having a score of 88.
Therefore,
Overall score = T + 88
Total student = x + 1
Average = 76
Average = overall score / total number of student
76 = (T + 88) /(x + 1)
Cross multiply
76(x + 1) = T + 88
Clear bracket
76x + 76 = T + 88
From equation 1
T = 72x
76x + 76 = 72x + 88
Collect like terms
76x – 72x = 88 – 76
4x = 12
Divide both side by the coefficient of x i.e 4
x = 12/4
x = 3
Therefore, the initial number of the student were 3.
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