P and C JEE quesn

BITSAT 2015 Online › Algebra questions › P and C JEE quesn

The sides AB , BC and CA of triangle ABC hav 3 , 4 and 5 interior pts. respectively on them. The no. of triangles that can be constructed using these interior pts. as vertices is??

#Mathematics #Algebra

UP 0 DOWN 0 0 8
Post on FacebookPost anonymously?

8 Answers

1

kunl ·2011-04-05 07:03:21

205 is what i think....n ofcourse i also think my answer is wrong[3]

UP 0 DOWN 0
Post on FacebookPost anonymously?

1

jee12 ·2011-04-05 07:50:15

i gues is shud be 220-3=217

UP 0 DOWN 0
Post on FacebookPost anonymously?

6

AKHIL ·2011-04-05 08:39:09

miracle!!!!!
kunl

its the rite ans:P

ab can u xplain a little abt this wonderful turnaround!!
:)

UP 0 DOWN 0
Post on FacebookPost anonymously?

6

AKHIL ·2011-04-05 23:52:59

the doubts i had were that the 1st the quesn is a bit confusing

interior pts on the sides

and then
nothin has been said abt the coliinearity of these pts!!

UP 0 DOWN 0
Post on FacebookPost anonymously?

30

Ashish Kothari ·2011-04-06 00:46:29

The solution is pretty simple - ¹²C₃ - ³C₃ - ⁴C₃ - ⁵C₃ .

The question says that the points are on the sides .

So we choose any three points arbitrarily, and then remove those cases where all the points are from the same side.

UP 0 DOWN 0
Post on FacebookPost anonymously?

6

AKHIL ·2011-04-06 03:29:22

thats fine

but what is the sense of interior pts. on side??

UP 0 DOWN 0
Post on FacebookPost anonymously?

30

Ashish Kothari ·2011-04-06 04:54:25

I think they tried to over-justify it and ended up doing the opposite. [3]

UP 0 DOWN 0
Post on FacebookPost anonymously?

6

AKHIL ·2011-04-06 09:36:31

ok
:)

UP 0 DOWN 0
Post on FacebookPost anonymously?

Your Answer

Basic Integral Calculus Operators Symbols Matrix Cases

√ √ || {} [] () → ~ ^ x x x → → ln log lg lim lim cos sin tan cot arcsin arccos arctan

∫ ∫ ∫ ∫ ∫ ∬ ∬ ∬ ∬ ∬ ∭ ∭ ∭ ∭ ∭ ⨌ ⨌ ⨌ ⨌ ⨌

∑ ∑ ∑ ∑ ∑ ∮ ∮ ∮ ∮ ∮ ∏ ∏ ∏ ∏ ∏ ∐ ∐ ∐ ∐ ∐

+ - × ÷ ± ∓ = ∪ ∩ ≠ ∼ ≈ ∅ ∀ ∃ ∈ ∋ ∝ ≤ ≥ ≃ ≅ ≡ < > ≪ ≫ ⊂ ∉ ⊃ ⊆ ⊇ ⇒ ⇐ ⇔ ⇒ ⇐ ⇔ ⇑ ⇓ ⇕ → ← ↔ → ← ↔ ↑ ↓ ↕ ↖ ↗ ↘ ↙ ↪ ↩ ⇀ ↼ ⇁ ↽

° ∂ ∞ α β γ δ θ λ μ ν ξ π ρ σ φ ω ε ƒ κ τ υ Γ Δ Λ Σ Π Ω