There are three points P, Q and R on a straight line such that PQ : QR = 3 : 5. If n is the number of possible values of PQ : PR, then what is n equal to ?
2
Given:
PQ : QR = 3 : 5
Calculation:
CASE - 1
Assuming PQ = 3x, QR = 5x and PR = PQ + QR, we get
PQ : PR = 3x : (3x + 5x)
⇒ PQ : PR = 3 : 8
CASE - 2
Assuming PQ = 3x, QR = 5x and PR = QR - PQ, we get
PQ : PR = 3x : (5x - 3x)
⇒ PQ : PR = 3 : 2
So, we have n = 2 possible values.
Hence, option 2 is correct.
The order of points is not fixed. So, we have to check for all other possible cases.
Mistake Points
Important Questions from Lines and Angles
Two parallel lines are intersected by a transversal, the corresponding angles are:
If l, m, n are lines such that, l is parallel to n and m is parallel to n, then, ______
Two cars start from a point at the same time and travel on two different roads at right angles to each other. Their speed is 18 km/h and 72 km/h respectively. What will be the distance between them after 6 seconds?
If angles of a triangle are in the ration of 2 : 3 : 4, then the measure of the smallest angle is:
If the angles of a triangle are in the ratio of 2 : 3 : 5, then find the ratio of the greatest angle to the smallest angle.
A. 7 : 2
B. 5 : 2
C. 5 : 3
D. 3 : 5
