2017 - WAEC Mathematics Past Questions and Answers - page 5
In a class of 45 students, 28 offer chemistry and 25 offer Biology. If each student offers at least one of the two subjects, calculate the probability that a student selected at random from the class the class offers chemistry only.
28 - x + x + 25 - x = 45
53 - x = 45
x = 53 - 45
x = 8
chemistry only = 28 - 8
= 20
Probability = \(\frac{20}{45}\)
= \(\frac{4}{9}\)
In the diagram, NQ//TS, <RTS = 50\(^o\) and <PRT = 100\(^o\). Find the value of <NPR
< TSR = 180 - (80 + 50)
= 180 - (130)
= 50\(^o\)
< QPR = < TSR corresponding < s
< NPR + QPR = < NPR
180\(^o\) - < QPR = < NPR
180\(^o\) - 50 = < NPR
< NPR = 130\(^o\)
A stationary boat is observed from a height of 100m. If the horizontal distance between the observer and the boat is 80m, calculate, correct to two decimal places, the angles of depression of the boat from point of observation
Tan \(x^o = \frac{100m}{80}\)
Tan \(x^o = Tan^{-1} 1.25\)
x = 51.34\(^o\)
The diagonal of a square is 60 cm. Calculate its peremeter
\(60^2 + x^2 + x^2\)
\(360^2 = 2x^2\)
\(x^2\) = 1800
x = \(\sqrt{1800}\)
x = 42.4264
x = 42.4264
perimeter = 4x
= 4 x 42.4264
= 169.7056
= 120\(\sqrt{2}\)
= 120\(\sqrt{2}\)
Find the value of m in the diagram
2x + m = 180
x + m = 112
x = 122 - m
2(112 - m) + m = 180
224 - 2m + m = 180
224 - m = 180
224 - 180 = m
m = 44\(^o\)
The graph of y = \(ax^2 + bx + c\) is shown oon the diagram. Find the minimum value of y
In the diagram, PR is a diameter of the circle RSP, RP is produced to T and TS is a tangent to the circle at S. If < PRS = 24\(^o\), calculate the value of < STR
RSP = 90 < substance in semi a circle
RPS = 180 - (90 + 24)
= 180 - (114)
= 66
TPS = 180 - 66
= 114
RST = 24
< STR = 180 - (114 + 24)
= 180 - 138
= 42\(^o\)