Question

The average of 1st three of 4 numbers is 16 and of the last three is 15, If the sum of the first and the

last number is 13 than What is the last number?​

Answer 1

Answer:

Step-by-step explanation:

average=sum of no./no. of observations

16=sum of numbers/3

sum of first three numbers=48

sum of last three numbers=45

sum of first and last number=13

let us assume

=u be the first no. and v be the last no.

and write u=13-v

sum of first three numbers

a1+a2+a3=48

13-v+a2+a3=48

sum of last three numbers

a2+a3+a4=45

a2+a3+v=45

subtracting 2 from 1

13-2v=3

16=2v

v=8

we know

first and last sum is 13

and first number=13-8

=5

the last number is 8