SSC CGL 2019 PYQ — Question 72

SSC CGL - 7th June 2019 - Shift 3 • Quantitative Aptitude • Q72

If (8x3 + 27y3) ÷ (2x + 3y) = (Ax2 + Bxy + Cy2),  then the value of (5A + 4B + 3C) is:

Show answer & explanation

Correct answer: D

Explanation

The correct answer is Option 4 i.e. 23

⇒ (8x3 + 27y3) ÷ (2x + 3y)

By using the identity, a3 + b3 = (a + b)(a2 + b2 + ab)

⇒ ((2x + 3y)(4x2 + 9y2 - 6xy))/(2x + 3y)

⇒ (4x2 + 9y2 - 6xy)

⇒ (Ax2 + Bxy + Cy2)

⇒ A = 4, B = -6 & C = 9

⇒ (5A + 4B + 3C) = 5(4) + 4(-6) + 3(9)

⇒ 20 - 24 + 27

⇒ 23