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WAEC 2019 · Paper 2 · Q8

  1. (a)

    The fifth term of an Arithmetic Progression (A.P.) is 11 and the eighth term is 20. Find the: (i) 12th term; (ii) sum of the first 12 terms.

    Separate values with commas, e.g. 3, −2

  2. (b)

    A trader collected ₦36,000.00 in cash after allowing a discount of 15%15\%. How much was the discount?

Worked solution (try it first)

(a)

  1. T5=a+4d=11T_5 = a + 4d = 11 and T8=a+7d=20T_8 = a + 7d = 20.
  2. Subtract: 3d=93d = 9, so d=3d = 3 and a=11−12=−1a = 11 - 12 = -1.

(i)

  1. T12=a+11d=−1+33=32T_{12} = a + 11d = -1 + 33 = 32.

(ii)

  1. S12=122(a+T12)S_{12} = \frac{12}{2}(a + T_{12})
    =6(−1+32)= 6(-1 + 32)
    =186= 186.

(b)

  1. After a 15%15\% discount he collected 85%85\% of the marked price: marked price =36 0000.85≈₦42,352.94= \frac{36\,000}{0.85} \approx ₦42,352.94.
  2. The discount was 42 352.94−36 000≈₦6,352.9442\,352.94 - 36\,000 \approx ₦6,352.94.

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