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If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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31 Jan 2017, 01:58
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If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30, what is the smallest number? A. 5 B. 10 C. 15 D. 20 E. 25
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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31 Jan 2017, 09:48
5x, 5(x+1), 5(x+2), 5(x+3), 5(x+4) are 5 multiples (50+25X)/5=30 X=4 5X ie smallest number = 20



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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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02 Feb 2017, 01:53
==> From 5n,5n+5, 5n+10, 5n+15, 5n+20, the average is 5n+10, and from 5n+10=30, you get 5n=20, n=4. The smallest number=5n=5(4)=20, hence the answer is D. Answer: D
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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02 Feb 2017, 10:48
MathRevolution wrote: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30, what is the smallest number?
A. 5 B. 10 C. 15 D. 20 E. 25 We can denote the first multiple of 5 as x and the last multiple of 5 as x + 20. Since we have an evenly spaced set of integers, we can use the following average formula: (least multiple of 5 in the set + greatest multiple of 5 in the set)/2 = average (x + x + 20)/2 = 30 2x + 20 = 60 2x = 40 x = 20 Thus, the smallest number in the set is 20. Answer: D
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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20 Mar 2017, 03:21
let the number be a , a+5, a+10, a+15, a+20 a +a +5 +a +10 +a+15+a+20 = 30*5 or 5a + 50 = 150 or a = 20 therefore the smallest number is 20
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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22 Mar 2017, 01:49
==> If the average of 5 consecutive multiples of 5 is 30, from 20,25,30,35,40, the smallest multiple of 5 becomes 20. Therefore, the answer is D. Answer: D
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If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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22 Mar 2017, 04:56
MathRevolution wrote: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30, what is the smallest number of them? A. 5 B. 10 C. 15 D. 20 E. 25 Concept: For Arithmetic progression (or equally spaced series) arithmetic mean = median. => Median = 30 (3rd term of the series). Smallest number or 1st element will be 20. Answer D. Thanks.



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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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22 Mar 2017, 06:08
let the number be x,x+5,x+10,x+15,x+20 avg is 30
so 30*5=5x+50 5x=100 x=20 answer is D



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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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22 Mar 2017, 10:32
MathRevolution wrote: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30, what is the smallest number of them? A. 5 B. 10 C. 15 D. 20 E. 25 \(5a + 5b + 5c + 5d + 5e = 150\) Now, If the smallest number is 20 then we have.... \(20 + 25 + 30 + 35 + 40 = 150\) Thus, answer must be (D) 20
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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28 Mar 2017, 04:27
Since the 5 numbers are consecutive multiples of 5 and the mean is 30 ,the middle number must be 30 so 20,25,30,35,40 Answer : D



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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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28 Mar 2017, 04:53
Let the numbers be n,n+5,n+10,n+15,n+20 ( because numbers are consecutive multiple of 5) Then (5n+50)/5=30 according to the question Solving which we get n=20 Answer D Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app



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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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08 Aug 2017, 01:46
For any A.P series => Mean = Median
Hence as number of terms = 5 Median => 3rd term.
Hence the series would be ==>
  30  
filling up the blanks => 20,25,30,35,40
Hence smallest => 20
Hence D.
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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10 Aug 2017, 09:52
MathRevolution wrote: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30, what is the smallest number of them? A. 5 B. 10 C. 15 D. 20 E. 25 Let’s let x = the smallest multiple of 5. The next consecutive multiple of 5 is (x + 5); the one after that will be (x + 10), and so on. We can create the following equation: x + x + 5 + x + 10 + x + 15 + x + 20 = 150 5x = 100 x = 20 Answer: D
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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09 Apr 2020, 20:05
Average is 30 and two consecutive multiple of 5 before 30 are 25 and 20. So 20 is the answer. Option D is the answer
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Re: If the average (arithmetic mean) of 5 consecutive multiples of 5 is 30
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