Let α,β,γ,δ∈Z and let A(α,β),B(1,0),C(γ,δ) and D(1,2) be the vertices of a parallelogram ABCD . If AB=10 and the points A and C lie on the line 3y=2x+1, then 2(α+β+γ+δ) is equal to
(A)10
(B)5
(C)12
(D)8✓ Correct
Answer: (D)
Solution
E, the common midpoint of the diagonals AC and BD of parallelogram ABCD, satisfies
2α+γ=21+1=1⟹α+γ=2,2β+δ=20+2=1⟹β+δ=2
So α+β+γ+δ=2+2=4, and
2(α+β+γ+δ)=8
(This is consistent with the additional constraints AB=10 and A,C on 3y=2x+1, which fix the individual integer values of α,β,γ,δ without changing this sum.)
JEE Main · 2024 · 31 Jan 2024 · Shift 1 · Single correct option