• 16.
Common difeference:
Is the difference between consecutive numbers in an arithematic sequence
18 -20 = -2
16-18 = -2
14-16 = -2
Common difference = -2
• 17.
Explicit rule: Use the arithematic sequence formula
an = a1 +(n-1 ) d
Where:
a1 = first term = 20
d= common difference = -2
Replacing:
an = 20 + (n-1)-2
• 18.
Replace n by 11
an = 20 + (11-1 ) -2
an = 20 + (10)-2
an= 20 - 20
an = 0
Amount to be paid = 0 (zero)
