JHS3 Mathematics · Term 2, Week 9
Variables and Equations
Full lesson notes coming
Notes for this lesson are being prepared. The curriculum details below are complete and ready to use for your planning.
Curriculum details
- Strand
- Algebra (Strand 2)
- Sub-strand
- Variables and Equations (2.3)
- Content standard
- B9.2.3.1 - Demonstrate understanding of single variable linear inequalities with rational coefficients including: • solving inequalities • verifying • comparing • graphing
- Indicator
- B9.2.3.1.3 - Solve real-life problems involving linear equations and inequalities.
- Suggested placement
-
Term 2, Week 9
(Week 21 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
- Curriculum reference
-
Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 193
Transcribed from the official NaCCA publication. Check this page against the source.
Exemplars (from the NaCCA curriculum)
E.g.1 Solve real-life problems involving linear equations. i. A man has 260metres of fencing which he is going to put around a rectangular field which is 50metres wide. How long is the field? Solution: Since we need to find the length of the field, let x metresbe
the length. x + 50 + x + 50 or 2(x + 50) But this expression is given as 260m ∴ 2(x + 50) = 260 x + 50 = 130 x = 80m ii. A man paid GH₵ 290 for 11 books. Some of the books were geography books, and the rest were history books. If each geography book cost GH₵ 30 and each history book cost GH₵20, how many geography books did he buy? Solution: i. Total cost of the books is GH₵290; total number of books is 11. ii. 1 geography book costs GH₵30; 1 history book costs GH₵20, Total cost of all the books is 30x + 20(11 - x) = 290 ∴ 30x + 20(11 - x) = 290 30x + 220 - 20x = 290 10x + 220 = 290 x = 7 Hence the number of geography books bought is 7. E.g.2 Solve real-life problems involving linear inequalities. i. Two sides of a triangle have lengths 6 cm and 8 cm. What is the length of the third side? Note: The sum of the lengths of the two sides of a triangle is greater than the length of the third side. If the third side is xcm long then, 6 + 8 > x giving x < 14.
Also, 6 + x < 8 giving x > 2. [Also, 8 + x > 6 whichgivesx > -2. Hence, 2 < x < 14. that is, the third side has length between 2cm and 14cm. ii. A student scores 70 and 76 marks in two tests. How many marks must she score in the third test to be put in Grade A if all students scoring an average of 80 or higher in three tests are put in grade A?