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WAEC 2012 · Paper 2 · Q7

  1. (a)

    If x=−14x = -\frac14, y=12y = \frac12 and z=−13z = -\frac13, evaluate x2−yz−x\dfrac{x^2 - y}{z - x}.

  2. (b)

    In one month, a man spent ₦650 on newspapers and ₦240 on soap. The next month, he reduced his newspaper spending by 40%40\%. If the ratio of the amount spent on soap in the second month to that of the first month is 5:35 : 3, what is the difference in the amount spent on both items in the two months?

Worked solution (try it first)

(a)

  1. Top: x2−y=116−12x^2 - y = \frac{1}{16} - \frac12
    =−716= -\frac{7}{16}.
  2. Bottom: z−x=−13−(−14)z - x = -\frac13 - \left(-\frac14\right)
    =−13+14= -\frac13 + \frac14
    =−112= -\frac{1}{12}.
  3. Divide: −716÷(−112)=716×12-\frac{7}{16} \div \left(-\frac{1}{12}\right) = \frac{7}{16} \times 12
    =8416= \frac{84}{16}
    =514= 5\frac14.

(b)

  1. First month: 650+240=₦890650 + 240 = ₦890.
  2. Second month: newspapers 0.6×650=₦3900.6 \times 650 = ₦390.
  3. Soap is 53\frac53 of 240, which is ₦400.
  4. Total ₦790.
  5. Difference =890−790=₦100= 890 - 790 = ₦100.

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