Question

There are four numbers average of first three is 15 and that of last is 16 if last no is 19 then first number​

Answer 1

Step-by-step explanation:

let the no. be a,b,c,d,

av. of first 3no. is 15

(a+b+c)/3=15

a+b+c=45

av. of last 3no. is 16

(b+c+d/3=48

b+c+d= 48

on subtracting

a+b+c-(b+c+d)=45-48

a+b+c-b-c-d= -3

a-d= -3

a-19=-3

a=19-3

a=16

hence first no. is 16

....666....