SSC CGL 2020 PYQ — Question 73

SSC CGL - 4th March 2020 Shift 1 • Quantitative Aptitude • Q73

In ΔABC, ∠A = 90o, M is the midpoint of BC and D is a point on BC such that AD ⊥ BC. If AB = 7 cm and AC = 24 cm, then AD : AM is equal to:

Show answer & explanation

Correct answer: A

Explanation

The correct answer is Option 1 i.e 336 : 625.

Understanding/Application

By triplet 7-24-25

BC = 25 cm

M is the mid-point of BC so,

BM = BC/2 = 25/2 = 12.5 cm

By property,

AM = BM = 12.5 cm

AD ⊥ BC

So, Triangles ADC and BAC are similar:

So, 

BC/AC = AB/AD

⇒ BC × AD = AC × AB

⇒ 25 × AD = 7 × 24

⇒ AD = 168/25 = 6.72

Hence,

AD : AM = 6.72 : 12.5 = 336 : 625