The mean weight of 25 students in a class is 58 kg. The mean weight of a second class of 29 students is 62 kg. How do you find the mean weight of all the students?

1 Answer
smendyka
Dec 15, 2016

The mean or average weight of all the students is 60.1 kg rounded to the nearest tenth.

Explanation:

This is a weighted average problem.

The formula for determining a weighted average is:

#color(red)(w = ((n_1 xx a_1) + (n_2 xx a_2))/(n_1 + n_2))#

Where #w# is the weighted average,

#n_1# is the number of objects in the first group and #a_1# is the average of the first group of objects.

#n_2# is the number of objects in the second group and #a_2# is the average of the second group of objects.

We were given #n_1# as 25 students, #a_1# as 58 kg, #n_2# as 29 students and #a_2# as 62 kg. Substituting these into the formula we can calculate #w#.

#w = ((25 xx 58) + (29 xx 62))/(25 + 29)#

#w = (1450 + 1798)/54#

#w = 3248/54#

#w = 60.1#

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