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Explanation:

Let number of 50, 10 and 1 miso notes used is x, y and z respectively.

⇒ 50x + 10y + z = 107

Now, since x, y and z are whole numbers x can take only three values i.e., 0, 1 and 2.

Case 1: x = 0
⇒ 10y + z = 107
⇒ y can take values from 0 till 10 i.e., 11 values
∴ 11 ways to pay bill of 107 misos.

Case 2: x = 1
⇒ 10y + z = 57
⇒ y can take values from 0 till 5 i.e., 6 values
∴ 6 ways to pay bill of 107 misos.

Case 3: x = 2
⇒ 10y + z = 7
⇒ y can take only 1 value i.e., 0
∴ 1 way to pay bill of 107 misos.

⇒ Total ways the bill can be paid = 11 + 6 + 1 = 18 ways,

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The bill can be paid in 18 ways as shown in the above table.

Hence, option (c).