Stepwise
Start practisingPractise

JAMB 1983 · UME · Q12

In a class of 60 pupils, the numbers offering Biology, History, French, Geography and Additional Mathematics are shown in the pie chart. How many pupils offer Additional Mathematics?

A. Maths 2x − 24Geog. xFrench x + 12History 2x + 12Biology 3x − 18
Sector angles are in degrees; A. Maths = Additional Mathematics, Geog. = Geography.
Worked solution (try it first)
  1. The angles at the centre of a pie chart add up to 360∘360^\circ: (2x−24)+(3x−18)+(2x+12)+(x+12)+x=360(2x - 24) + (3x - 18) + (2x + 12) + (x + 12) + x = 360.
  2. Collect terms: 9x−18=3609x - 18 = 360, so 9x=3789x = 378 and x=42x = 42.
  3. Additional Mathematics has angle 2(42)−24=60∘2(42) - 24 = 60^\circ.
  4. Its share of the 60 pupils is 60360×60=10\frac{60}{360} \times 60 = 10, option B.

Report a problem with this question