The mean and variance of ' n 'observations x1,x2,x3,…,xn are 6 and 0, respectively. If ∑i=1n xi2=900, then the value of n is equal to

Given mean x¯=6 and  variance σ2=∑i=1n xi−x¯2n=0⇒x1−62+x2−62+……+xn−62=0⇒x1=x2=……..=xn=6 ( ∵ Sum of perfect squares will be zero, when each of them is zero)  Given that ∑i=1n xi2=900⇒n⋅62=900∴n=25