The table shows how much Kylie saves daily. For each subsequent day, she saves $8 more than the previous day.
- How much will Kylie save on Day 11?
- On which day will Kylie save $42?
- How much savings will Kylie have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 8 + 10 = $18
Day 2: 2 x 8 + 10 = $26
Day 3: 3 x 8 + 10 = $34
Day 4: 4 x 8 + 10 = $42
Formula
Amount saved = Day Number x 8 + 10
Amount saved on Day 11
= 11 x 8 + 10
= $98
(b)
Number of days that Kylie takes to save $42
= (42 - 10) ÷ 8
= 32 ÷ 8
= 4
(c)
Total savings that Kylie saves by Day 4
= 18 + 26 + ... + 34 + 42
= (18 + 42) x (4 ÷ 2)
= 60 x 2
= $120
Answer(s): (a) $98; (b) 4; (c) $120
