What is the greatest possible length which can be used to measure exactly the lengths 180 m, 500 m and 15m 20 cm?
Choose the correct answer
A) 80 cm
B) 50 cm
C) 40 cm
D) 10 cm
E) 100 cm

Rationale: required length = hcf of 18000 cm , 50000 cm , 1520 cm = 80 cm answer is a
Answer: A