Question
Question: A particle is at A(1, 2). It can move either horizontally or vertically by 1 unit in each step. The ...
A particle is at A(1, 2). It can move either horizontally or vertically by 1 unit in each step. The no. of ways can it reach B(4, 6) by travelling in shortest path.
A
7C2
B
7!
C
7
D
7C3
Answer
7C3
Explanation
Solution
There are 3 horizontal and 4 vertical steps.
This is similar to arranging 3Hs' and 4V's in 7 places.
No. of ways = ∠3∠4∠7=7C3