Sequences
2 marks · HardIn a science experiment, Marta adds chemicals to a solution following this sequence: she adds 2 ml on the first day, 5 ml on the second day, 8 ml on the third day, and so on, increasing the amount by 3 ml each day.
On which day will she add exactly 44 ml to the solution?
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15 (±0)
Also accept: Day 15
Common mistakes: Giving the term value (44) instead of its position (n); Calculating n = 14 or n = 16 due to errors setting up the formula
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Sets up correct nth term formula or equation for the sequence, i.e. uses , , and sets .
A1 · 1 mark · Solves for correctly. (follow-through)
Worked solution
This is an arithmetic sequence with first term and common difference .
So, on day 15, she adds 44 ml.