The table shows how much Abi saves daily. For each subsequent day, she saves $3 more than the previous day.
- How much will Abi save on Day 10?
- On which day will Abi save $196?
- 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 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 10
= 10 x 3 + 10
= $40
(b)
Number of days that Abi takes to save $196
= (196 - 10) ÷ 3
= 186 ÷ 3
= 62
(c)
Total savings that Abi saves by Day 62
= 13 + 16 + ... + 193 + 196
= (13 + 196) x (62 ÷ 2)
= 209 x 31
= $6479
Answer(s): (a) $40; (b) 62; (c) $6479