The table shows how much Gabby saves daily. For each subsequent day, she saves $5 more than the previous day.
- How much will Gabby save on Day 8?
- On which day will Gabby save $200?
- How much savings will Gabby have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 5 + 10 = $15
Day 2: 2 x 5 + 10 = $20
Day 3: 3 x 5 + 10 = $25
Day 4: 4 x 5 + 10 = $30
Formula
Amount saved = Day Number x 5 + 10
Amount saved on Day 8
= 8 x 5 + 10
= $50
(b)
Number of days that Gabby takes to save $200
= (200 - 10) ÷ 5
= 190 ÷ 5
= 38
(c)
Total savings that Gabby saves by Day 38
= 15 + 20 + ... + 195 + 200
= (15 + 200) x (38 ÷ 2)
= 215 x 19
= $4085
Answer(s): (a) $50; (b) 38; (c) $4085
