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Question
primary 6 | Maths
| Data Analysis
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Sos
Date Posted: 2 years ago
Views: 497
average of n numbers = 124.5
sum = 124.5 * n
Keyed 135 instead of 153
sum = 124.5*n - 135 + 153
sum = 124.5*n + 18
actual average = 129
sum = 129*n
124.5*n + 18 = 129*n
129n - 124.5n = 18
4.5n = 18
n = 18/4.5 = 4
4 numbers were there.
sum = 124.5 * n
Keyed 135 instead of 153
sum = 124.5*n - 135 + 153
sum = 124.5*n + 18
actual average = 129
sum = 129*n
124.5*n + 18 = 129*n
129n - 124.5n = 18
4.5n = 18
n = 18/4.5 = 4
4 numbers were there.
Ans: 4
153-135 = 18
129-124.5 = 4.5
18÷4.5 = 4 (Ans)
153-135 = 18
129-124.5 = 4.5
18÷4.5 = 4 (Ans)
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