# maths

posted by
**puk**
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3. An elastic string hangs from a nail N. When as mass of m grams is attached to its lower end, the elastic is stretched so that its lower length is x cm, as shown in the diagram:

N The table shows result of the two experiments:

Length (x cm) 43 49

Mass (m grams) 50 80

m

It is known that x and m are connected by the equation x = c + dm, where c and d are constants.

(a) Solve your equations to find the value of c and the value of d.

(b) Find the mass at the end of the string when its length is 40 cm.

(c) What does the value of c represents?