Answer:
3- 5- 1
^ ^ ^
1 -5, 1,3 3,5
Step-by-step explanation:
Complete Question
Let P (n) be the statement that a postage of n cents can be formed using just 4-cent stamps and 7-cent stamps. The parts of this exercise outline a strong induction proof that P (n) is true for n ≥ 18.
Show statements P (18), P (19), P (20), and P (21) are true, completing the basis step of the proof.
Answer:
P(18) is true
P(19) is true
P(20) is true
P(21) is true
Step-by-step explanation:
a. When n = 18
18 cents can be formed using two 7cents and one 4cents
i.e. 2 * 7 + 4 = 18
So, P(18) is true
b. When n = 19
19 cents can be formed using one 7cents and three 4cents
i.e. 1 * 7 + 3 * 4 = 19
So, P(19) is true
c. When n = 20
18 cents can be formed using five 4cents
i.e. 5 * 4 = 20
So, P(20) is true
d. When n = 21
18 cents can be formed using three 7cents
i.e. 3 * 7 = 21
So, P(21) is true
