The table shows how much Rachel saves daily. For each subsequent day, she saves $4 more than the previous day.
- How much will Rachel save on Day 6?
- On which day will Rachel save $190?
- How much savings will Rachel have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 4 + 10 = $14
Day 2: 2 x 4 + 10 = $18
Day 3: 3 x 4 + 10 = $22
Day 4: 4 x 4 + 10 = $26
Formula
Amount saved = Day Number x 4 + 10
Amount saved on Day 6
= 6 x 4 + 10
= $34
(b)
Number of days that Rachel takes to save $190
= (190 - 10) ÷ 4
= 180 ÷ 4
= 45
(c)
Total savings that Rachel saves by Day 45
= 14 + 18 + ... + 186 + 190
= (14 + 190) x (45 ÷ 2)
= 204 x 22.5
= $4590
Answer(s): (a) $34; (b) 45; (c) $4590