Question

average of 40 numbers is 27 average of 1st 30 numbers is 17 and next 9 is 8 . then what is last number

Answer 1

rate the answer also......please!!!!!!

Answer 2

Let the numbers be x1,x2,x3 ..........x40

$\frac{x1+x2+x3+.................................+x40}{40} =27$$x1+x2+x3+x4+....................+x40 = 27 X 40$

$x1+x2+x3................................+x40= 1080$

We also have $\frac{x1+x2+x3+.................x30}{30} =17$

$x1+x2+x3+...............x30 = 17 X30$

$x1+x2+x3....................+x30 = 510$ ________________(1)

and we also have

$\frac{x31+x32+x33+..........x39}{9} =8$

$x31+x32+x33+..............+x39=72$

Now lets's plug in these value in our equation

[$[x1+x2+x3.............+x30]+[x31+x32+........x39]+x40=1080$[tex]

510+72+x40 = 1080

x40 = 1080-510-72

x40 = 498

The last number is 498