The table shows how much Dana saves daily. For each subsequent day, she saves $10 more than the previous day.
- How much will Dana save on Day 5?
- On which day will Dana save $60?
- 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 10 + 10 = $20
Day 2: 2 x 10 + 10 = $30
Day 3: 3 x 10 + 10 = $40
Day 4: 4 x 10 + 10 = $50
Formula
Amount saved = Day Number x 10 + 10
Amount saved on Day 5
= 5 x 10 + 10
= $60
(b)
Number of days that Dana takes to save $60
= (60 - 10) ÷ 10
= 50 ÷ 10
= 5
(c)
Total savings that Dana saves by Day 5
= 20 + 30 + ... + 50 + 60
= (20 + 60) x (5 ÷ 2)
= 80 x 2.5
= $200
Answer(s): (a) $60; (b) 5; (c) $200
