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rakeshd347
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Q: Angle made by the linesrakeshd347 wrote:At what angle do lines y=Kx+B and y=Bx+K intersect ?
(1) B+K=1
(2) BK=0
y = Kx + B ... (i)
y = Bx + K ... (ii)
We need the values of K and B both to find the equations of the 2 lines.
St1:
B + K = 1
Many numbers satisfy this equation. B = 0, K = 1; B = 2, K = -1 ... Thus we dont have a definite answer for the Slope and the Intercept of the lines (i) & (ii)
INSUFFICIENT
St2:
BK = 0
We can have three cases here
1) B = 0; (i) becomes y = Kx (ii) becomes y = K (We still need the value of K)
2) K = 0; (i) becomes y = B (ii) becomes y = Bx (We still need the value of B)
3) B = K = 0; The two equations become the X Axis itself.
All the three cases are possible, So the statement is INSUFFICIENT
St1+St2:
Now we know that the sum must be equal to 1; Case 3 of st2 becomes invalid.
1) B = 0; K = 1 (Since B + K = 1); (i) becomes y = x (ii) becomes y = 1
1) K = 0; B = 1 (Since B + K = 1); (i) becomes y = 1 (ii) becomes y = x
The two equations are y = 1 & y = x and the angle made by them is 45.
SUFFICIENT.
Answer C
Regards,
Vivek
