Question

there are 4 numbers. Average of first three is 15 and that of last three is 16, if the last number is 19 find the first number​

Answer 1

Answer:

Answer is 1

Step-by-step explanation:

Let us suppose the 3 numbers be x,y,z

Now it is given that average of first three is 15

so (x+y+z)/3=15 => x+y+z=30..........(p)

Now it is given that the last number is 19

so the average of last 3 =>  (y+z+19)/3=16

y+z=29 ..........(1)

put the value of 1 in  p

x+29=30

x=1

Answer 2

Answer:

Step-by-step explanation:

let x1,x2,x3,x4 are four numbers

(x1+x2+x3)/3=15

x1+x2+x3=45...........(1)

(x2+x3+x4)/3=16

x2+x3+x4=48.........(2)

solving (1) and (2)

x1-x4=-3

x1-19=-3

x1=16