A-LevelMathematicsSeries9709/12 · Oct/Nov 2011 · Q1010 Marks
(a) An arithmetic progression contains 25 terms and the first term is –15. The sum of all the terms in the progression is 525. Calculate (b) A college agrees a sponsorship deal in which grants will be received each year for sports equipment. This grant will be $4000 in 2012 and will increase by 5% each year. Calculate
- (a)(i)the common difference of the progression,[2]
- (a)(ii)the last term in the progression,[2]
- (a)(iii)the sum of all the positive terms in the progression.[2]
- (b)(i)the value of the grant in 2022,[2]
- (b)(ii)the total amount the college will receive in the years 2012 to 2022 inclusive.[2]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2011). The mark or mark type is shown in brackets.
- [2] Use of Sn → d = 3.
- [2] Last term = a + 24d
- [2] → 57
- [2] Positive terms are 3,6, ....57
- [2] Use of S19 or S20
- [2] → 570
- [2] 11th term = ar¹⁰ = $6516 or $6520
- [2] S₁₁ = 4000×(1.05¹¹ – 1) / 0.05
- [2] = $56800 or (56827)
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →