The table shows how much Cindy saves daily. For each subsequent day, she saves $3 more than the previous day.
- How much will Cindy save on Day 6?
- On which day will Cindy save $103?
- How much savings will Cindy have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 3 + 10 = $13
Day 2: 2 x 3 + 10 = $16
Day 3: 3 x 3 + 10 = $19
Day 4: 4 x 3 + 10 = $22
Formula
Amount saved = Day Number x 3 + 10
Amount saved on Day 6
= 6 x 3 + 10
= $28
(b)
Number of days that Cindy takes to save $103
= (103 - 10) ÷ 3
= 93 ÷ 3
= 31
(c)
Total savings that Cindy saves by Day 31
= 13 + 16 + ... + 100 + 103
= (13 + 103) x (31 ÷ 2)
= 116 x 15.5
= $1798
Answer(s): (a) $28; (b) 31; (c) $1798
