Let two roots of a quadratic equation are mean =np and variance =npq. Given np+npq=82.5 and np(npq)=1350 ∴ Quadratic equation is x2−82.5x+1350=0 ⇒x2−22.5x−60x+1350=0 ⇒x−(x−22.5)−60(x−22.5)=0 Mean =60 and Variance =22.5 np=60,npq=22.5 ⇒q=‌