Higher June 2023 Paper 2 Q18
18 \(2a : 5c = 6 : 25\)
\(4b : 7c = 20 : 21\)
Show that \(a + b : b + c = 17 : 20\) (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| Shown | M1 | for start to method to find a ratio connecting 2 of \(a\), \(b\) and \(c\), eg \(a : c = 3 : 5\) oe or \(b : c = 5 : 3\) oe or for start to method to combine ratios, eg \(14a : 35c\ (= 126 : 525)\) and \(20b : 35c\ (= 500 : 525)\) |
| M1 | for method to find \(a : b : c\), eg 9 : 25 : 15 oe or for method to write \(a + b : b + c\) in terms of one variable eg \(\dfrac{3c}{5} + \dfrac{5c}{3} : \dfrac{5c}{3} + c\) | |
| A1 | for \(a + b : b + c = 34 : 40\) oe leading to result |
Additional guidance
May be expressed in fractional form
Any ratios must be clearly assigned to variables
34 : 40 may be seen as \(9 + 25 : 25 + 15\)