The table shows how much Abi saves daily. For each subsequent day, she saves $4 more than the previous day.
- How much will Abi save on Day 5?
- On which day will Abi save $154?
- How much savings will Abi have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 4 + 10 = $14
Day 2: 2 x 4 + 10 = $18
Day 3: 3 x 4 + 10 = $22
Day 4: 4 x 4 + 10 = $26
Formula
Amount saved = Day Number x 4 + 10
Amount saved on Day 5
= 5 x 4 + 10
= $30
(b)
Number of days that Abi takes to save $154
= (154 - 10) ÷ 4
= 144 ÷ 4
= 36
(c)
Total savings that Abi saves by Day 36
= 14 + 18 + ... + 150 + 154
= (14 + 154) x (36 ÷ 2)
= 168 x 18
= $3024
Answer(s): (a) $30; (b) 36; (c) $3024
