Skip to content
MathsGenie logo
Quick links
Open app

Course home

  1. A Level
  3. Maths OCR (MEI)
  5. Question bank

1.6.13 Standard formulae for arithmetic series (A-level only)

Medium
1234567891011121314151617181920212223242526272829303132333435363738
Question 26

In a sustainable construction project, the number of solar panels installed during each of the first three months is represented by the following expressions:

4k−1,7k−5,12k−19 4k - 1, \quad 7k - 5, \quad 12k - 19 4k−1,7k−5,12k−19
a.

Show that k=5k = 5k=5 is the unique value for which these monthly installation figures form an arithmetic sequence.

[3]
bi.

State the number of panels installed in the first month.

[1]
bii.

Determine the common difference for this sequence.

[1]
c.

The total number of solar panels installed after NNN months is given by SNS_NSN​.

Given that

SN<25 000 S_N < 25\,000 SN​<25000 SN+1>25 000 S_{N+1} > 25\,000 SN+1​>25000

Find the value of NNN.

[5]

1.6.13 Standard formulae for arithmetic series (A-level only) Questions

  1. A Level
  2. /Maths
  3. /1.6.13 Standard formulae for arithmetic series (A-level only)