The table shows how much Kathy saves daily. For each subsequent day, she saves $8 more than the previous day.
- How much will Kathy save on Day 8?
- On which day will Kathy save $74?
- How much savings will Kathy 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 8
= 8 x 8 + 10
= $74
(b)
Number of days that Kathy takes to save $74
= (74 - 10) ÷ 8
= 64 ÷ 8
= 8
(c)
Total savings that Kathy saves by Day 8
= 18 + 26 + ... + 66 + 74
= (18 + 74) x (8 ÷ 2)
= 92 x 4
= $368
Answer(s): (a) $74; (b) 8; (c) $368