The table shows how much Olivia saves daily. For each subsequent day, she saves $4 more than the previous day.
- How much will Olivia save on Day 10?
- On which day will Olivia save $150?
- How much savings will Olivia 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 10
= 10 x 4 + 10
= $50
(b)
Number of days that Olivia takes to save $150
= (150 - 10) ÷ 4
= 140 ÷ 4
= 35
(c)
Total savings that Olivia saves by Day 35
= 14 + 18 + ... + 146 + 150
= (14 + 150) x (35 ÷ 2)
= 164 x 17.5
= $2870
Answer(s): (a) $50; (b) 35; (c) $2870
