Harold calculated the mean of 5 numbers to be 68. Then he found that he had made an error and had written 70 for one of the numbers when he should have written 80. What is the mean of the correct 5 numbers? Explain how you found your answer.
2007-02-27 08:17:53 · 4 answers · asked by exxohh<3 1 in Education & Reference ➔ Homework Help
68 x 5= 340
80-70=10
340+10=350
350/5=70
2007-02-27 08:22:19 · answer #1 · answered by Cerebal 3 · 1⤊ 0⤋
The mean is 70.
So you know that mean is the sum of all the answers divided by the number of things being added.
So all you do is work backwards. If 68 is your answer, the last thing Harold must have done was divide the sum by five. You ought to do the opposite, so multiply by five. You should get 340.
You know that this is the sum of all the other numbers and that one of the numbers is 70. You also know that he should have added 80 instead. The difference between 70 and 80 is ten.
add ten to the sum. you get 350. Now that you have the correct sum, divide by five to get the mean. You should get 70.
2007-02-27 16:29:24 · answer #2 · answered by buttercup 3 · 0⤊ 0⤋
The mean is 70 because by definition the mean is the sum div. by the number of terms.
Since the mean was 68, the sum had to 68*5 = 340. Now you know the sum is actually 340 + 10, so your final answer is 350 / 5
2007-02-27 16:20:50 · answer #3 · answered by scruffy 5 · 1⤊ 1⤋
the mean is the sum divided by the number of numbers.
His sum was too big by 10, so his answer was too big by 10/5...
2007-02-27 16:22:52 · answer #4 · answered by k_e_p_l_e_r 3 · 0⤊ 1⤋