What is the greatest possible length which can be used to measure exactly the lengths 10 m, 14 m 50 cm and 20 m 40cm cm?  Select the correct option:	A) 20 cm	B) 10 cm	C) 25cm	D) 50 cm	E) 28 cm
Required length = HCF of 1000 cm, 1450 cm, 2040 cm = 10cm   Answer is 10 cm
<result>B</result>
What is the greatest possible length which can be used to measure exactly the lengths 10 m, 14 m 50 cm and 20 m 40cm cm?