JAMB - Mathematics (1983 - No. 38)
In a class of 60 pupils, the statistical distribution of the numbers of pupils offering Biology, History, French, Geography and Additional mathematics is as shown in the pie chart. How many pupils offer Additional Mathematics?
15
10
18
12
20
Explication
(2x - 24)° + (3x - 18)° + (2x + 12)° + (x + 12)° + x° = 360°
9x = 360° + 18°
x = \(\frac{378}{9}\)
= 42°, if x = 42°, then add maths = \(\frac{2x - 42}{360}\) x 60
= \(\frac{2 \times 42 - 24}{360}\) x 60
= \(\frac{84 - 24}{6}\)
= 10
9x = 360° + 18°
x = \(\frac{378}{9}\)
= 42°, if x = 42°, then add maths = \(\frac{2x - 42}{360}\) x 60
= \(\frac{2 \times 42 - 24}{360}\) x 60
= \(\frac{84 - 24}{6}\)
= 10