Question

The mean of seven number is 15 when three numbers is added, the mean of the ten numbers is 12. Find the three numbers

Answer 1

Answer:

Given:

1) mean of 7 numbers is 15

after adding 3 numbers to it

2)mean of 10 numbers  is 12

let us assume  that three numbers as a,b and c

also let x be the sum of that first 7 numbers

mean=sum of all numbers /number of given numbers

15=x/7

15x7=x

x=105

Now, let us go to second case

mean=sum of numbers/number of numbers

12=x+a+b+c/10

12=105+a+b+c/10

12x10=105+a+b+c

120=105+a+b+c

120-105=a+b+c

15=a+b+c

so,

a=5

b=5 and

c=5

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