Q: 80 (NDA-I/2012)

Two thin convex lenses of focal lengths 4 cm and 8 cm are separated by a distance of 4 cm in air. The combination will have the focal length
question_subject: 
Maths
question_year: 
2012
question_exam: 
NDA-I
stats: 
0,56,120,56,32,72,16