The table shows how much Emma saves daily. For each subsequent day, she saves $3 more than the previous day.
- How much will Emma save on Day 9?
- On which day will Emma save $88?
- How much savings will Emma have in total by the day found in part (b)?
(a)
Pattern for the amount saved
Day 1: 1 x 3 + 10 = $13
Day 2: 2 x 3 + 10 = $16
Day 3: 3 x 3 + 10 = $19
Day 4: 4 x 3 + 10 = $22
Formula
Amount saved = Day Number x 3 + 10
Amount saved on Day 9
= 9 x 3 + 10
= $37
(b)
Number of days that Emma takes to save $88
= (88 - 10) ÷ 3
= 78 ÷ 3
= 26
(c)
Total savings that Emma saves by Day 26
= 13 + 16 + ... + 85 + 88
= (13 + 88) x (26 ÷ 2)
= 101 x 13
= $1313
Answer(s): (a) $37; (b) 26; (c) $1313