10 A bill of 135 naira was paid using 5 naira note and 10 naira note. If 16 notes were used altogether, find how many of each were used.

Let's denote the number of 5 naira notes as x and the number of 10 naira notes as y. We are given that the total amount paid is 135 naira and the total number of notes used is 16. We can set up the following system of equations:5x + 10y = 135 (1)x + y = 16 (2)We can solve this system of equations using substitution or elimination. Let's use substitution:From equation (2), we can express x as x = 16 - y. Substituting this into equation (1), we get:5(16 - y) + 10y = 13580 - 5y + 10y = 1355y = 55y = 11Now that we have the value of y, we can substitute it back into equation (2) to find the value of x:x + 11 = 16x = 5Therefore, 5 of the 5 naira notes were used, and 11 of the 10 naira notes were used.