Moderate -0.3 This is a straightforward application of standard arithmetic progression formulas (a + d = 11 and S_40 = 3030) requiring students to set up and solve two simultaneous equations. While it involves multiple steps, the techniques are routine and commonly practiced, making it slightly easier than average for A-level.
Question 3:
3 | (i)a + d = 11 oe
20(2a + 39d) = 3030 oe
correct initial step in solving simultaneously
d = 3.5 oe
a = 7.5 oe | M1*
M1*
M1dep*
A1
A1
[5] | eg 20(2(11 – d) + 39d) = 3030 oe,
SC1 if either of first two marks not awarded
SC1 if either of first two marks not awarded | may be implied by correct answers
mark to benefit of candidate
mark to benefit of candidate
In an arithmetic progression, the second term is 11 and the sum of the first 40 terms is 3030. Find the first term and the common difference. [5]
\hfill \mbox{\textit{OCR MEI C2 Q3 [5]}}