The table shows how much Shiyun saves daily. For each subsequent day, she saves $6 more than the previous day.
- How much will Shiyun save on Day 10?
- On which day will Shiyun save $196?
- How much savings will Shiyun 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 10
= 10 x 6 + 10
= $70
(b)
Number of days that Shiyun takes to save $196
= (196 - 10) ÷ 6
= 186 ÷ 6
= 31
(c)
Total savings that Shiyun saves by Day 31
= 16 + 22 + ... + 190 + 196
= (16 + 196) x (31 ÷ 2)
= 212 x 15.5
= $3286
Answer(s): (a) $70; (b) 31; (c) $3286