a, b, c, d, and e are five consecutive numbers in increasing order

Question

a, b, c, d, and e are five consecutive numbers in increasing order of size. Deleting one of the five
numbers from the set decreased the sum of the remaining numbers in the set by 20%. Which one of
the following numbers was deleted?

(A) a
(B) b
(C) c
(D) d
(E) e

Source: GMAT Math Bible

(A) a
(B) b
(C) c
(D) d
(E) e

Source: GMAT Math Bible

Alnuaimi · Answer

Let's say that those numbers are , 1,2,3,4,5. So the sum will be 15. Now what is the 20% of 15 ? It's gonna be 3. So 15-3= 12 which is the sum of 1+2+4+5 .....

duahsolo · Answer

a+b+c+d+e => 1+2+3+4+5=15

20%*15= 3 =>c

chetan2u · Answer

Hi,
five consecutive numbers will have average as the centre number, c.
sum =5*c..
we want 20% less= 5c*80/100=4c..
the number being deducted=5c-4c=c..
C

MathRevolution · Answer

Let's test the condition with the data series: 1(a), 2(b), 3(c), 4(d), 5(e)

1 + 2 + 3 + 4 + 5 = 15

=> 20% reduction on the sum (15) =  \frac{80 }{ 100} * 15 = 12

=> For sum to be '12', remove '3' from 15.

Answer C

Abhishek009 · Answer

Let ,  a > b > c > d > e = 2 > 4 > 6 > 8 > 10

Or,  a + b + c + d + e = 30

Or,  a + b + c + d = 24

Thus, the number deleted is (C) c, Answer

EyeSeaMe · Answer

Since all the mentioned numbers are integers in increasing order -

Let a, b, c, d, & e be equal to 0, 1, 2, 3, & 4 respectively.

Sum of all the numbers = 0 + 1 + 2 + 3 + 4 = 10

Since deleting a number decreases the sum by 20 %, we see that -

a = 0 will have no effect.

Deleting 1 from the set will make the new sum = 9, & using the concept of percentage change we get -

9 - 10 / 10 = -10 %

So we move to the next higher number i.e. 2, and we get the desired results.

Answer is Option C

jarn · Answer

Since we have consecutive integers A, B, C, D, E we know:
A = A
B = A+1
C= A+2
D = A+3
E = A+4

Sum of these is 5a + 10. To reduce that by 20%, we take out one A, and then reduce 10 by 20% (essentially .8 * 10 = 8). Removing term C (A+2) would equal that reduction

bumpbot · Answer

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a, b, c, d, and e are five consecutive numbers in increasing order

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a, b, c, d, and e are five consecutive numbers in increasing order

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