The table shows how much Dana saves daily. For each subsequent day, she saves $6 more than the previous day.
- How much will Dana save on Day 11?
- On which day will Dana save $70?
- How much savings will Dana have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 6 + 10 = $16
Day 2: 2 x 6 + 10 = $22
Day 3: 3 x 6 + 10 = $28
Day 4: 4 x 6 + 10 = $34
Formula
Amount saved = Day Number x 6 + 10
Amount saved on Day 11
= 11 x 6 + 10
= $76
(b)
Number of days that Dana takes to save $70
= (70 - 10) ÷ 6
= 60 ÷ 6
= 10
(c)
Total savings that Dana saves by Day 10
= 16 + 22 + ... + 64 + 70
= (16 + 70) x (10 ÷ 2)
= 86 x 5
= $430
Answer(s): (a) $76; (b) 10; (c) $430