The table shows how much Anna saves daily. For each subsequent day, she saves $5 more than the previous day.
- How much will Anna save on Day 6?
- On which day will Anna save $135?
- How much savings will Anna 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 6
= 6 x 5 + 10
= $40
(b)
Number of days that Anna takes to save $135
= (135 - 10) ÷ 5
= 125 ÷ 5
= 25
(c)
Total savings that Anna saves by Day 25
= 15 + 20 + ... + 130 + 135
= (15 + 135) x (25 ÷ 2)
= 150 x 12.5
= $1875
Answer(s): (a) $40; (b) 25; (c) $1875
