The average of all the numbers which are the first ten multiples of each of the first ten natural numbers is

10 multiples of

1:1,2,3,4,5,6,7,8,9,10

2:2,4,6,8,10,12,14,16,18,20

And so on but if you observe here,

If 2 is taken out from the series we get,2(1+2+3+4+5+6+7+8+9+10)

Therefore the series comes out to be

S=1(1+2+3+4+…..+10) +2(1+2+3+4+5+6+…+10)+3(1+2+3+4+5+6+…+10)+4(1+2+3+4+5+6+…+10)+5(1+2+3+4+5+6+…+10)+5(1+2+3+4+5+6+…+10)+…….+10(1+2+3+4+5+….+10)

S=(1+2+3+4+5+6+7+8+9+10)(1+2+3+4+5+6+7+8+9+10)

S=((10*11)/2)*((10*11)/2)

S=(110*110)/4

That is the sum comes out to be S

Average is S/100 since there are total 100 numbers

This implies

A=(110*110)/(4*100)

A=121/4=30.25.

A is correct choice.