1999 - WAEC Mathematics Past Questions and Answers - page 4

Total number of mangoes = m

Amina ate 3 mangoes \(\implies\) Remainder = m - 3

Shared equally with Uche \(\implies \frac{m - 3}{2}\)

\(\frac{m - 3}{2} \geq 10\)

\(x^2 + 15x + 50 = 0\)

\(x^2 + 5x + 10x + 50 = 0\)

\(x(x + 5) + 10(x + 5) = 0\)

\((x + 5)(x + 10) = 0\)

x + 5 = 0 or x + 10 = 0.

Comparing \(x^2 + 15x + 50\) with \(ax^2 + bx + c\), b = 15 and c = 50.

\(\therefore\) bc = 750.

x = -m \(\implies\) x + m = 0;

x = 2n \(\implies\) x - 2n = 0.

\(\implies (x + m)(x - 2n) = 0\)

\(x^2 + mx - 2nx - 2mn = 0\)

\(x^2 + x(m - 2n) - 2mn = 0\)

P(man picked at random wears size 9 shoes) = \(\frac{28}{100}\)

= \(\frac{7}{25}\)