Higher June 2018 Paper 1 Q13
13 \(\sqrt{5}\left(\sqrt{8} + \sqrt{18}\right)\) can be written in the form \(a\sqrt{10}\) where \(a\) is an integer.
Find the value of \(a\). (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| 5 | M1 | for \(\sqrt{40}\) or \(\sqrt{90}\) OR \(2\sqrt{2}\) or \(3\sqrt{2}\) |
| M1 | for \(2\sqrt{10}\) or \(3\sqrt{10}\) or \(\sqrt{4} \times \sqrt{10}\) or \(\sqrt{9} \times \sqrt{10}\) or \(\sqrt{4 \times 10}\) or \(\sqrt{9 \times 10}\) OR \(2\sqrt{2} + 3\sqrt{2}\) | |
| A1 | cao |
Additional guidance
Answer of \(5\sqrt{10}\) from correct working gets M2 A0