Answer:
At the end of Week 20;
Seth has 58 balls
Matt has 20 balls
Seth has more balls
Step-by-step explanation:
The graph shows a progression
Week 1:
Matt has 1, Seth has 22
Week 5:
Matt has 5, Seth has 30:
Week 9:
Matt has 9, Seth has 38
For Matt, the progression shows that;
Matt bought (5 - 1) baseball's between week 1 and 5 and (9 - 5) between week 9 and 5
(5 - 1) balls = (9 - 5) balls
=> 4 balls = 4 balls
(9 - 5) weeks = (5-1) weeks
4 weeks = 4 weeks
4 weeks = 4 balls. --- divide by 4
1 weeks = 1 ball
This means that Matt buys a ball per week; Common difference = 1
For Matt, the progression shows that;
Matt bought (30 - 22) baseball's between week 1 and 5 and (38 - 30) between week 9 and 5
(30 - 22) balls = (38 - 30) balls
=> 8 balls = 8 balls
(9 - 5) weeks = (5-1) weeks
4 weeks = 4 weeks
4 weeks = 8 balls. --- divide by 4
1 seek = 2 ball
This means that Sett buys 2 balls ball per week --- Common difference = 2
Calculating their balls at week 20;
Using the following formula
Tn = a + (n-1)d.
Where a = first term
n = nth term
d = common difference
For Matt
a = 1
d = 1
n = 20
Tn = a + (n-1)d becomes
T20 = 1 + (20 - 1) * 1
T20 = 1 + 19 * 1
T20 = 20
For Seth
a = 22
d = 2
n = 20
Tn = a + (n-1)d becomes
T20 = 22 + (20 - 1) * 2
T20 = 22 + 19 * 2
T20 = 22 + 38
T20 = 58.
At the end of Week 20;
Seth has 58 balls
Matt has 20 balls
Seth has more balls
