2017 - WAEC Mathematics Past Questions and Answers - page 1
Express 0.0000407, correct to 2 significant figures
If x varies inversely as y and y varies directly as z, what is the relationship between x and z?
\(x \propto \frac{1}{y}\), y \(\propto\) z
x = \(\frac{k}{y}\)
y = mz
Since y = mz,
x = \(\frac{k}{mz}\), where k and m are constants. Hence,
x \(\propto\) \(\frac{1}{z}\)
Evaluate \(\frac{3\frac{1}{4} \times 1\frac{3}{5}}{11\frac{1}{3} - 5 \frac{1}{3}}\)
\(\frac{3\frac{1}{4} \times 1\frac{3}{5}}{11\frac{1}{3} - 5 \frac{1}{3}}\) = \(\frac{\frac{26}{5}}{\frac{18}{3}}\) = \(\frac{26}{5} \div \frac{18}{3}\)
= \(\frac{13}{15}\)
The ages of Tunde and Ola are in the ratio 1:2. If the ratio of Ola's age to Musa's age is 4:5, what is the ratio of Tunde's age to Musa's age?
Tunde: Ola \(\to\) 1 : 2 ; Ola; Musa \(\to\) 4 : 5
\(\frac{1}{2}\) x \(\frac{4}{5}\)
= \(\frac{2}{5}\)
If M = {x : 3 \(\leq\) x < 8} and N = {x : 8 < x \(\leq\) 12}, which of the following is true?
i. 8 \(\in\) M \(\cap\) N
ii. 8 \(\in\) M \(\cup\) N
iii. M \(\cap\) N = \(\varnothing\)
Given that a = log 7 and b = \(\log\) 2, express log 35 in terms of a and b.
\(\frac{\log 7 \times \log 10}{\log 2}\)
log 7 x log 10 \(\div\) log 2
a + 1 - b
a - b + 1
If x = \(\frac{2}{3}\) and y = - 6, evaluate xy - \(\frac{y}{x}\)
x = \(\frac{2}{3}\) and y = - 6
xy - \(\frac{y}{x}\)
\(\frac{2}{3} - (6)^2 - (-6) \div \frac{2}{3}\)
= -4 - (6) x \(\frac{3}{2}\)
= -4 - (-6) x \(\frac{3}{2}\)
= -4 - (-9)
= -4 + 9
= 5
Solve the equation: \(\frac{1}{5x} + \frac{1}{x}\)= 3
\(\frac{1}{5x} + \frac{1}{x}\)= 3
\(\frac{1 + 5}{5x}\) = 3
6 = 15x
x = \(\frac{6}{15}\)
= \(\frac{2}{5}\)
A sum of N18,100 was shared among 5 boys and 4 girls with each boy taking N20.00 more than each girl. Find a boy's share.
Let a girl's share = x + 20
4x + 5(x + 20) = 18,100
4x + 5x + 100 = 18,100
9x + 100 = 18,100
9x = 18,000
x = \(\frac{18,000}{9}\)
x = 2,000
\(\therefore\) Each boy gets N(2,000 + 20)
= N2,020.
One factor of \(7x^2 + 33x - 10\) is
\(7x^2 + 33x - 10\)
\(7x^2 + 35x - 2x - 10\)
7x (x + 5) - 2 (x + 5)
(7x - 2) (x + 5)