DIRECTIONSfor the question:Solve the following question and mark the b...
Suppose N = S9 = n + (n + 1) + (n + 2)….. + (n + 8) = 9(n + 4).
N can also be written as :
S10 = a + (a + 1) + … + (a + 9) = 5(2a + 9) or S11 = x + (x + 1) + … + (x + 10) = 11(x + 5).
Since N = S9 = S10 = S11, we know that N must be divisible by 9, 5 and 11.
So, the smallest value of N must be LCM (5, 9, 11) = 495.
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DIRECTIONSfor the question:Solve the following question and mark the b...
Question Analysis:
We are given that a positive integer N can be expressed as the sum of 9 consecutive integers, 10 consecutive integers, and 11 consecutive integers. We need to find the smallest value of N.
Solution:
Let's assume that the middle term of the 9 consecutive integers is x.
So, the 9 consecutive integers will be (x-4), (x-3), (x-2), (x-1), x, (x+1), (x+2), (x+3), and (x+4).
Similarly, let's assume that the middle term of the 10 consecutive integers is y.
So, the 10 consecutive integers will be (y-4), (y-3), (y-2), (y-1), y, (y+1), (y+2), (y+3), (y+4), and (y+5).
Also, let's assume that the middle term of the 11 consecutive integers is z.
So, the 11 consecutive integers will be (z-5), (z-4), (z-3), (z-2), (z-1), z, (z+1), (z+2), (z+3), (z+4), and (z+5).
Sum of 9 consecutive integers:
The sum of 9 consecutive integers can be calculated using the formula:
Sum = Number of terms * (First term + Last term) / 2
In this case, the sum of 9 consecutive integers will be:
N = 9 * (x-4 + x+4) / 2
= 9 * (2x) / 2
= 9x
Sum of 10 consecutive integers:
The sum of 10 consecutive integers can be calculated using the formula:
Sum = Number of terms * (First term + Last term) / 2
In this case, the sum of 10 consecutive integers will be:
N = 10 * (y-4 + y+5) / 2
= 10 * (2y + 1) / 2
= 5(2y + 1)
Sum of 11 consecutive integers:
The sum of 11 consecutive integers can be calculated using the formula:
Sum = Number of terms * (First term + Last term) / 2
In this case, the sum of 11 consecutive integers will be:
N = 11 * (z-5 + z+5) / 2
= 11 * (2z) / 2
= 11z
Comparing the sums:
From the above calculations, we can see that N = 9x = 5(2y + 1) = 11z.
Let's find the smallest value of N by comparing the sums of the three consecutive integers.
Comparing N = 9x and N = 5(2y + 1):
Since N is a positive integer, both 9x and 5(2y + 1) should be positive integers.
The smallest positive integer value for 9x is 9, and for 5(2y + 1) is 5