Question

the average of 6 number is 30 if the average of first four is 25 and that of last three is 35 the fourth number is

Answer 1

Let the six numbers be a,b,c,d,e,f   respectively

Given their average

(a+b+c+d+e+f)/6=30

So,a+b+c+d+e+f=180          ...............Eq.(1)

(a+b+c+d)/4=25

=>a+b+c+d=100                 ................Eq.(2)

(d+e+f)/3=35

=>d+e+f=105                      .................Eq.(3)

Adding Eq.(2) and Eq.(3) and subtracting Eq,(1) from it

We get,  d=25

So the fourth number is 25.

Thanks!!!

Answer 2

Answer:

Step-by-step explanation:

✌️Sum of 6 numbers =60×30=180

✌️Sum of first 4 numbers =4×25=100

✌️Sum of last 3 numbers =3×35=105

∴ Fourth number =(100+105)−180

=205−180

=25♥️✌️

♥️✌️I hope you understand ☺️♥️