What is the greatest possible length which can be used to measure exactly the lengths 180 m, 500 m and 15m 20 cm? Pick:  A) 80 cm  B) 50 cm  C) 40 cm  D) 10 cm  E) 100 cm
Required length = HCF of 18000 cm, 50000 cm, 1520 cm = 80 cm   80 cmnswer is 80 cm
<result>A</result>
What is the greatest possible length which can be used to measure exactly the lengths 180 m, 500 m and 15m 20 cm?