SOLUTION: Average mass of a group of people is 45.2kg. A newcomer to the group weighs 51kg, which increases the average by 0.2kg How many people are now in the group?
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Question 563890: Average mass of a group of people is 45.2kg. A newcomer to the group weighs 51kg, which increases the average by 0.2kg How many people are now in the group?
This is a question which needs a quadratic equation to be set up in the form ax˛+bx+c=0 so that it can be solved using the quadratic formula. I just can't figure out how to set it up. Please help me! :-)
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
let the number in the group be x
total mass = x*45.2 =45.2x
One person joins so the total mass = 45.2x+ 51
The number of people = x+1
Average of the group =
=
45.4(x+1)=45.2x+51
45.4x+45.4=45.2+51
45.4x-45.2x=51-45.4
0.2x=5.6
/0.2
x=28
there are 29 in the group now
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