Source: Previous Question Papers

Find the value of 31×32×30×33+1\sqrt{31\times32\times30\times33+1}

Options

Option A

990

Option B

923

Option C

1021

Option D is correct

991

Explanation

Let the given expression be E=31×32×30×33+1E = \sqrt{31\times32\times30\times33+1}. We can rearrange the terms as E=30×31×32×33+1E = \sqrt{30\times31\times32\times33+1}. Let x=30x = 30. Then the expression becomes E=x(x+1)(x+2)(x+3)+1E = \sqrt{x(x+1)(x+2)(x+3)+1}. We can group the terms: E=[x(x+3)][(x+1)(x+2)]+1E = \sqrt{[x(x+3)][(x+1)(x+2)]+1}. This simplifies to E=(x2+3x)(x2+3x+2)+1E = \sqrt{(x^2+3x)(x^2+3x+2)+1}. Let y=x2+3xy = x^2+3x. Substituting yy into the expression, we get: E=y(y+2)+1E = \sqrt{y(y+2)+1} E=y2+2y+1E = \sqrt{y^2+2y+1} E=(y+1)2E = \sqrt{(y+1)^2} E=y+1E = |y+1| Since x=30x=30, y=302+3(30)=900+90=990y = 30^2+3(30) = 900+90 = 990. Therefore, E=990+1=991E = |990+1| = 991. Thus, the value of the expression is 991991.