Logic and methodology would be appreciated.
2006-10-22 10:28:30 · 5 answers · asked by sattarsoul 2 in Science & Mathematics ➔ Mathematics
ONE
The total for 25 would have to be 125
The total for 31 would have to be 124
so....ONE!
2006-10-22 10:31:58 · answer #1 · answered by MollyMAM 6 · 0⤊ 0⤋
From the first statement, you have:
( a + b + c + d + e )/5 = 25
which can be written:
a + b + c + d + e = 125
Since we're going to remove a number, I'll put parentheses around the first four numbers. Note that this does not change the result:
(a + b + c + d) + e = 125
From the second statement, you have:
( a + b + c + d )/4 = 31
which can be written:
(a + b + c + d) = 124
Thus, you can substitute 124 anywhere you see (a+b+c+d), so we have:
124 + e = 125
Thus, the fifth number that was removed (which I've called "e") must be 1.
It makes sense that the removed number must have been far below the original average. That's why the new average is so much higher than the original average. That removed number was an outlier bringing the entire average down.
2006-10-22 10:40:08 · answer #2 · answered by Ted 4 · 1⤊ 0⤋
You began with SUM/5 = 25, so the five numbers SUM to 125.
Now you have removed one number, x,
so the average is (125 - x)/4 = 31. Multiply both sides by 4 and you get 125 - x = 124. Here, x = 1. (Note you divide by 4 since there are 4 remaining numbers).
2006-10-22 10:36:19 · answer #3 · answered by Action 4 · 1⤊ 0⤋
the sum of the five original numbers is 125, and the sum of the remaining 4 numbers is 124, so the number removed must be 1.
2006-10-22 10:31:00 · answer #4 · answered by Mr. Chemistry 2 · 1⤊ 0⤋
(a + b + c + d + e)/5 = 25
a + b + c + d + e = 125
(a + b + c + d)/4 = 31
a + b + c + d = 124
So this is saying
(124 + e)/5 = 25
124 + e = 125
e = 1
The number 1 was taken out.
ANS : 1
2006-10-22 11:24:46 · answer #5 · answered by Sherman81 6 · 0⤊ 0⤋